托福真题回忆 丨11月17日 托福考试详细机经
Environmental Science 环境科学
The Influence of Volcanic Eruption on Climate
Volcanoes and Climate Change
Mount Tambora dominates the small Indonesian island of Sumbawa in the Flores Sea east of Java. In 1815 it exploded in the largest eruption in the last 20,000 years, ejecting between 125 and 175 cubic kilometers of pumice (a type of rock formed by volcanoes) and ash. The year after the eruption, 1816, would become known as the"year without a summer. "Climate is influenced by many processes operating simultaneously, so the precise effect of Tambora is not easily gauged. The eruption was coincident with a span of several decades, from about 1790 to 1830, of colder climate apparently caused by a considerable decrease in solar activity. The years 1812 to 1818 were among the coldest of these, and this may have been primarily a result of the change in solar activity. It is also possible that the other large eruptions that occurred in that decade-Soufriere Hills (Montserrat, 1812). Mayon(Philippines 1814), Colima (Mexico,1814), and Beerenberg (North Atlantic 1818)-contributed to the cold conditions. Sparseness of climate records adds to this uncertainty. Much of our knowledge comes from tree rings and other natural recorders of time and climate.
How. exactly. do volcanic eruptions modify climate? Until recently, it was thought that dust in the form of particles of volcanic ash simply blocked incoming sunlight, and thus that the explosiveness of an eruption and the amount of solid material blown into the atmosphere were important parameters. We now know, however, that the effects of dust are negligible because it simply does not remain in the atmosphere long enough to block sunlight. Far more important is the amount of sulfur dioxide injected into the stratosphere, the base of which is about 10 to 15 kilometers high. In the atmosphere, sulfur dioxide reacts rapidly with water vapor to form sulfuric acid. Sulfuric acid forms an acrosol, a cloud of submicroscopic droplets less than a ten-thousandth of millimeter in diameter enough that the droplets do not rapidly settle. In contrast, in the troposphere, which extends from the stratosphere to Earths surface, precipitation rapidly washes out sulfuric acid and other pollutants.(This cannot happen in the stratosphere because it is above the clouds. The aerosol in the stratosphere absorbs some solar radiation, thereby causing cooling of the troposphere. Fortunately for life, the aerosol remains in the stratosphere for only a few years, so the effect of cataclysmic eruptions on climate is temporary.
The 1815 Tambora magma (liquefied rock found under the surface of Earth)was unusually rich in sulfur, and the eruption injected about 85 million tons of sulfur dioxide into the atmosphere. This is less than the current annual anthropogenic (created by humans)production of 130 million tons. However anthropogenic sulfur dioxide has little influence on climate because it is confined to the troposphere and is rapidly removed as acid rain. Other eruptions that injected large amounts of sulfur into the stratosphere were Krakatau (Indonesia, 1883). Gunung Agung(Indonesia, 1963). El Chichon(Mexico, 1982), and Mount Pinatubo(Philippines, 1991). All were followed by several years of unusually cool climate.
Sulfuric acid aerosols are also a major factor in the destruction of the ozone layer, which occupies the lower part of the stratosphere. For example, the Pinatubo eruption is estimated to have caused a 15 to 25 percent decrease in ozone in the high latitudes. Exactly how the aerosol affects ozone is not precisely known. One possibility is that the droplets provide sites for the breakdown of otherwise inert chlorine compounds and in that way enhance the formation of atomic chlorine, which is known to destroy ozone.
The Tambora magma was also rich in chlorine. The fate of chlorine in the atmosphere is not well understood. Hydrochloric acid, which has hydrogen and chlorine atoms, is soluble (easily dissolved) in water, absorbs ash particles, and thus probably is removed from the atmosphere as water or ash rain. Even if hydrochloric acid does reach the stratosphere, its effect on ozone is unclear because hydrochloric acid itself does not react with ozone. Anthropogenic chlorofluorocarbons reside in the stratosphere for long periods of time, however, and the atomic chlorine formed as chlorofluorocarbons break down clearly does destroy ozone.
1. The word"simultaneously" in the passage is closest in meaning to
C. in similar ways
D. at the same time
2. In paragraph 1, why does the author discuss levels of solar activity?
A. To argue that decreased levels of solar activity may lead to increased volcanic activity on Earth
B. To explain how tree rings function as natural recorders of time and climate
C. To provide an example of a theory about climate change that has been proven incorrect
D. To provide an additional explanation for the period of cold that followed the Tambora eruption
3. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
A. The amount of dust blown into the atmosphere and the force with which it was ejected were once thought to be key factors because dust was believed to block sunlight.
B. Important parameters in blocking out sunlight include the explosiveness of an eruption and the amount of solid material blown into the atmosphere.
C. Until recently, it was thought that the accumulation of solid material blown into the atmosphere from volcanic eruptions was simply not sufficient to block incoming sunlight.
D. Until recently, it was difficult to say how much incoming sunlight was blocked by particles of volcanic ash in the atmosphere.
4. The word"thereby"in the passage is closest in meaning to
A. in the same area
B. by that means
C. in the meantime
5. According to paragraph 2, which of the following is true of the aerosol formed by sulfuric acid?
A. The aerosol quickly falls down through the atmosphere.
B. The aerosol has no effect on solar radiation.
C. The aerosol only remains in the stratosphere for a few years.
D. The aerosol is washed out by water vapor in the stratosphere.
6. Paragraphs 2 and 3 support which of the following statements about pollutants and their location within the atmosphere?
A. Pollutants remain in the troposphere longer than in the stratosphere.
B. Pollutants must occur in both the stratosphere and the troposphere in order to have a noticeable effect on climate.
C. Rain washes pollutants out of the stratosphere and into the troposphere.
D. Pollutants in the stratosphere have a greater effect on climate than those in the troposphere.
7. According to paragraph 3, why does anthropogenic sulfur dioxide affect the climate less than sulfur dioxide from volcanoes does?
A. Anthropogenic sulfur dioxide does not remain in the atmosphere as long as sulfur dioxide from volcanoes does.
B. There is much less anthropogenic sulfur dioxide in the atmosphere than there is sulfur dioxide from volcanoes.
C. Anthropogenic sulfur dioxide does not become acid rain as sulfur dioxide from volcanoes does.
D. Anthropogenic sulfur dioxide is less affected by periods of cooling than sulfur dioxide from volcanoes is.
8. According to paragraph 5, all of the following are true about hydrochloric acid in the atmosphere EXCEPT:
A. It is easily dissolved in water.
B. It may leave the atmosphere in the form of rainwater.
C. It frequently rises to the stratosphere where it remains for a long time.
D. It lacks the ability to react with ozone.
9. Whether or not this is the mechanism, it is known that less ozone results in lower temperatures.
A. ozone layer, which occupies the lower part of the stratosphere.@2
B. caused a 15 to 25 percent decrease in ozone in the high latitudes.@2
C. One possibility is that the droplets provide sites for the@1
D. atomic chlorine, which is known to destroy ozone.@2
10. Although it is hard to isolate the effects of volcanoes on climate, major eruptions may cause temperatures to drop.
A. Dust from volcanic eruptions does not stay in the atmosphere long, but it can significantly affect temperatures by blocking incoming sunlight.
B. Sulfuric acid aerosols contribute to the destruction of the ozone layer and thus cause colder temperatures,perhaps by leading to the breakdown of chlorine compounds already in the atmosphere.
C. Recent studies have shown that dust and ash from volcanic eruptions may have a longelasting effect on climate than was previously thought.
D. When sulfur dioxide released by volcanic eruptions reacts with water vapor to form sulfuric acid, it forms an aerosol that remains in the stratosphere for several years and absorbs some solar radiation.
E. Unlike the effects of anthropogenic chlorofluorocarbons , which do destroy ozone, the effects of chlorine from volcanic magma on ozone are not clear.
F. Cooling of the troposphere may actually be due to anthropogenic sulfur dioxide rather than sulfur dioxide released into the troposphere by volcanic eruptions.
The Nile Flood
Egypt Circa 3100 B.C.
The city of Memphis, located on the Nile near the modern city of Cairo, was founded around 3100 B.C., as the first capital of a recently united Egypt. The choice of Memphis by Egypt’s first kinds reflects the site’s strategic importance. First, and most obvious, the apex of the Nile River delta was a politically opportune location for the state’s administrative center, standing between the united lands of Upper and Lower Egypt and offering ready access to both parts of the country. The older predynastic (pre- 3100 B.C.) centers of power. This and Hierakonpolis, were too remote from the vast expanse of the delta, which had been incorporated into the unified state. Only a city within easy reach of both the Nile valley to the south and the more spread out, difficult terrain to the north could provide the necessary political control that the rulers of early dynastic Egypt (roughly 3000-2600 B.C.) required.
The region of Memphis must have also served as an important node for transport and communications, even before the unification of Egypt. The region probably acted as a conduit for much, if not all, of the river-based trade between northern and southern Egypt. Moreover, commodities (such as wine, precious oils, and metals) imported from the Near East by the royal courts of predynastic Upper Egypt would have been channeled through the Memphis region on their way south. In short, therefor, the site Memphis offered the rulers of the Early Dynastic Period an ideal location for controlling internal trade within their realm, an essential requirement for a state-directed economy that depended on the movement of goods.
Equally important for the national administration was the ability to control communications within Egypt. The Nile provided the easiest and quickest artery of communication, and the national capital was, again, ideally located in this respect. Recent geological surveys of the Memphis region have revealed much about its topography in ancient times. It appears that the location of Memphis may have been even more advantageous for controlling trade, transport, and communications than was previously appreciated. Surveys and drill cores have shown that the level of the Nile floodplain has steadily risen over the last five millenniums. When the floodplain was much lower, as it would have been in predynastic and early dynastic ties, the outwash fans (fan-shaped deposits of sediments) of various wadis (stream-beds or channels) that carry water only during rainy periods) would have been much more prominent features on the east bank. The fan associated with the Wadi Hof extended a significant way into the Nile floodplain, forming a constriction in the vicinity of Memphis. The valley may has narrowed at this point to a mere three kilometers, making it the ideal place for controlling river traffic.
Furthermore, the Memphis region seems to have been favorably located for the control not only of river-based trade but also of desert trade routes. The two outwash fans in the area gave access to the extensive wadi systems of the eastern desert. In predynastic times, the Wadi Digla may have served as a trade route between the Memphis region and the Near East, to judge from the unusual concentration of foreign artifacts found in the predynastic settlement of Maadi. Access to, and control of , trade routes between Egypt and the Near East seems to have been a preoccupation of Egypt’s rulers during the period of state formation. The desire to monopolize foreign trade may have been one of the primary factors behind the political unification of Egypt. The foundation of the national capital at the junction of an important trade route with the Nile valley is not likely to have been accidental. Moreover, the Wadis Hof and Digla provided the Memphis region with accessible desert pasturage. As was the case with the cities of Hierakonpolis and Elkab, the combination within the same area of both desert pasturage and alluvial arable land (land suitable for growing crops) was a particularly attractive one for early settlement, this combination no doubt contributed to the prosperity of the Memphis region from early predynastic times.
1. The word “vast” in the passage is closet in meaning to
2. According to paragraph 1, why was Memphis a better choice for the capital of a united Egypt than either This or Hierakonpolis?
A. Memphis was in a better location for maintaining administrative control.
B. Memphis had long been a regional administrative center by the time Egypt was united.
C. This and Hierakonpolis had never actually been incorporated into the unified state.
D. Egyptian rulers had failed to keep political control over This and Hierakonpolis in predynastic times.
3. It can be inferred from paragraph 1 that one consequence of the unification of Egypt was
A. the reduction of the strategic importance of older centers of power
B. the opportunity for the recently united Egypt to become economically self-sufficient
C. the increase in political tensions between the rulers of Upper and Lower Egypt
D. the reduction of Egypt’s dependence upon the Nile for trade and communications
4. Which of the following best describes how paragraph 1 is organized?
A. Two simultaneous developments are described, as well as the reasons why neither one would have occurred without the other.
B. A hypothesis is presented, and then points in favor of that hypothesis as well as points against it are discussed.
C. A major event is described, and then the most obvious effects of that event are presented.
D. A decision is described, and then one likely motivation for that decision is presented.
5. According to paragraph 2, when did Egypt import goods from the Near East?
A. Once internal trade was fully controlled from Memphis
B. Not until early dynastic Egypt established its state-directed economy
C. As early as predynastic times
D. Only when local supplies of those goods had been completely used up
6. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
A. Thus in Memphis, the rulers of the Early Dynastic Period were ideally placed to control internal trade, which they had to do in order to run their economy.
B. Therefore the rulers of the Early Dynastic Period thought Memphis was the ideal location for trade with nearby countries.
C. In short, a state-directed economy like that of the Early Dynastic Periodrequires choosing a single location to which goods can be moved-Memphis, in this case
D. In sum, then, a state-directed economy first developed during Egypt’s Early Dynastic Period because Memphis was an ideal location for controlling trade.
7. The word “appreciated” in the passage is closest in meaning to
8. According to paragraph 3, recent research into the topography of the Memphis region in ancient times suggests which of the following?
A. The level of the Nile floodplains was much higher in predynastic and dynastic times than in later times.
B. The sediment deposits of wadis were not as noticeable in predynastic and dynastic times than in later times.
C. The Nile valley at the point of Memphis was narrower in predynastic and dynastic times than it was in later times
D. Frequent rainy periods may have caused a significant reduction of trade traffic during the predynastic and dynastic times.
9. The word “vicinity” in the passage is closest in meaning to
D. surrounding area
10. According to paragraph 4, which of the following is NOT a reason Memphis was chosen as the capital of a united Egypt?
A. It was at the junction of a major trade route with the Nile valley.
B. It was near land that could be used for animal grazing and for growing crops.
C. The nearby outwash fans led into wadis that could be used as desert trade routes.
D. Since foreign traders had settled in nearby Maadi, trade between the two cities could be established.
11. The phrase “to have been accidental” in the passage is closest in
A. to have gone wrong
B. to have been helpful
C. to have occurred by chance
D. to have made a difference
12. In paragraph 4, why does the author mention the cities of Hierakonpolis and Elkab?
A. To give an indication of the level of prosperity that Memphis is thought to have enjoyed from its earliest days
B. To compare the Memphis region to them in terms of their similar combinations of characteristics providing advantages for early settlement
C. To identify the models that the founders of Memphis followed in laying out the national capital
D. To suggest that the combination of desert pasturage and alluvial arable land in the same area was very common
13. While considerations of political power and ease of administration were decisive in choosing the location of the new capital, the site clearly had other advantages.
A. The region of Memphis must have also@1@4
B. The region probably acted as a conduit@1@4
C. northern and southern Egypt.@2@4
D. through the Memphis region on their way south.@2@4
14. Around 3100 B.C. Memphis was chosen for its strategic importance to be the first capital of a recently united Egypt.
A. River-based trade from northern Egypt and imported goods going south all passed through the Memphis region, making Memphis an ideal location for controlling trade.
B. Recent geological surveys suggest that the topographical features of the Memphis region made it particularly well-suited for controlling communications and trade.
C. The rulers of unified Egypt enjoyed a monopoly over foreign trade because all such trade was required to go through the Wadi Digla, to which the rulers controlled all access.
D. After Memphis became the capital city, river-based trade along the Nile gained in importance, while land-based desert trade declined in importance.
E. The Nile, despite a constriction of its valley near Memphis, was the most advantageous route for communication and travel once the floodplain had begun to rise.
F. While the location of Memphis was agriculturally favorable, it was particularly attractive because it enabled Egypt’s rulers to control trade moving through the desert from the Near East.
Recognizing Social Play in Animals
Recognizing Social Play in Animals
Many animals engage in some type of social play-that is, playing with others including chasing and fighting. Three functions of social play have been proposed: Social play may(1)lead to the forging of long-lasting social bonds, (2)help develop much needed physical skills, such as those relating to fighting, hunting, and mating, and (3) aid in the development of cognitive skills. One cognitively related benefit of social play revolves around the idea of self-assessment. Here, animals use social play as means to monitor their developmental progress as compared to others. For example, in infant sable antelope (Hippotragus niger), individuals prefer same-age- play partners. While this preference could be due to numerous factors, Kaci Thompson has hypothesized that it is primarily a function of infants attempting to choose play partners that provide them with a reasonable comparison from which to gauge their own development.
Since many of the behavior patterns seen during play are also common in other contexts-hunting, mating, dangerous aggressive contests-how do animals know they are playing and not engaged in the real activity? And even more to the point how do they communicate this information to each other? Bekoff has proposed three possible solutions to this important, but often overlooked, question. One way that animals may distinguish play from related activities is that the order and frequency of behavioral components of play is often quite different from that of the real activity. That is, when play behavior is compared with the adult functional behavior that it resembles, behavioral patterns during play are often exaggerated and misplaced. If young animals are able to distinguish these exaggerations and misorderings of behavioral patterns by, for example observing adults that are not involved in play, a relatively simple explanation exists for how animals know they are playing.
A second, somewhat related, means by which animals may be able to distinguish play from other activities is by the placement of play markers. These are also known as play signals and can serve both to initiate play and to indicate the desire to continue playing and to warn adults that the young are playing and not in danger of injury. In canids(the animal group that includes dogs and wolves), for example, biting and shaking are usually performed during dangerous activities such as fighting and predation. Yet, biting and shaking are also play behaviors of young canids. Bekoff found that play markers such as a bow (lowering the head) would precede biting and rapid side-to-side shaking of the head to indicate that they were not dangerous behaviors. The bow would communicate that this action should be viewed in a new context-that of play. Another play marker might be a particular kind of vocalization-for example, chirping in a rat, whistling in a mongoose, panting in a wolf or a chimpanzee before or during a play interaction. Or there might be a distinctive smell that indicated that the animals were engaged in play.
Play markers have also been found in primates such as the juvenile lowland gorilla. Juvenile lowland gorillas play with each other often, and play ranges from what Elisabetta Palagi and her colleagues call gentle play to rough play. Palagi's team discovered that when juvenile gorillas-particularly males-were involved with rough play, the play was often preceded by a facial gesture they call the play face. This facial gesture, which is not seen in other contexts, includes slightly lowered eyebrows and an open mouth. In addition to using this facial gesture during rough play, juvenile gorillas also displayed it when a play session was in a place that made escape (leaving)difficult -another context in which it may be important to signal to others that what is about to occur is play.
Yet another way by which young animals may be able to distinguish play from related behaviors is by role reversal, or selfhandicapping, on the part of any older playmates they may have. In role reversal and self-handicapping, older individuals either allow subordinate younger animals to act as if they are dominant during play or the older animals perform some act (for example, an aggressive act) at a level clearly below that of which they are capable. Either of these provides younger playmates with the opportunity to recognize that they are involved in a play encounter.
1. The phrase"forging of" in the passage is closest in meaning to
A. increase of
B. support for
C. creation of
D. desire for
2. According to paragraph 1, young animals can judge how well they are developing by
A. engaging in fighting with other members of their species
B. establishing social bonds with individuals that have successfully developed physical skills
C. participating in play with a large number of different play partners
D. choosing to play with other animals that are close to them in age
3. According to paragraph 2, which of the following may signal that animals are playing rather than engaging in real activity?
A. By repeating a single component of a behavior rather than including all of the components
B. Performing actions in a different sequence than they are performed in during real activity
C. Performing actions that are appropriate for younger animals but not the animal performing the actions
D. Using certain behaviors only when adults are available to observe interactions among animals
4. Why does the author point out that"biting and shaking are also play behaviors of young canids"?
A. To provide examples of activities that sometimes function as play markers
B. To indicate that certain play behaviors are identical to behaviors that are unrelated to play
C. To point out that some types of play behavior are performed by several different species
D. To identify activities that are performed to indicate the desire to continue playing
5. The word "distinctive" in the passage is closest in meaning to
6. It can be inferred from paragraph 3 that in the absence of play signals, adult animals would
A. perceive young animals as being in danger of injury during play activity
B. be unable to give warnings to young animals that were in danger of injury
C. engage more frequently in dangerous activities such as fighting and predation
D. use side-to-side shaking of the head to indicate that biting was not dangerous
7. According to paragraph 4, one reason juvenile gorillas use play markers is that juvenile gorillas
A. cannot distinguish between different types of play
B. sometimes play in areas where it is difficult for them to get away
C. cannot distinguish facial gestures used during play from those used during real activity
D. need to indicate when play should become less rough
8. Paragraph 4 suggests which of the following about the use of play markers by lowland gorillas?
A. Lowland gorillas tend to use play markers most often during gentle play.
B. Female lowland gorillas use play markers more often than male lowland gorillas do.
C. Lowland gorillas mainly use play markers to signal that they do not want to play.
D. Lowland gorillas are one of several primate species that use play markers.
9. While this and other play markers are meant to be seen, not all play markers are visual.
A. head to indicate that they were not dangerous behaviors.@2
B. action should be viewed in a new context-that of play.@2
C. panting in a wolf or a chimpanzee before or during a play interaction.@2
D. distinctive smell that indicated that the animals were engaged in play.@2
10. Many animals participate in social play, which helps develop social relationships and improves physical and cognitive skills.
A. Much social play mimics dangerous behaviors such as hunting and fighting, so animals must have ways to signal to one another that play is happening, rather than something more serious.
B. Play signals, which animals use to indicate that they want to play, may include facial expressions, gestures or behaviors (such as bowing), vocalizations or giving off a certain smell.
C. One of the main benefits of play is that it allows young animals to develop their individual way of communicating through signals such as vocalizations and facial gestures.
D. Some behavioral elements used in play closely resemble those used during serious aggressive activities, but adults also engage in role reversal and self-handicapping when playing with youngsters.
E. Young animals must develop the cognitive skills needed to limit social play because play activity can lead to exaggerations and misorderings of behavior that are dangerous to them.
F. Adults primarily use play markers to indicate to young animals that they are not in danger of injury during play activity in which the adult engages in biting, shaking, or other rough behavior.
Running Water on Mars
Photographic evidence suggests that liquid water once existed in great quantity on the surface of Mars. Two types of flow features are seen: runoff channels and outflow channels. Runoff channels are found in the southern highlands. These flow features are extensive systems―sometimes hundreds of kilometers in total length―of interconnecting, twisting channels that seem to merge into larger, wider channels. They bear a strong resemblance to river systems on Earth, and geologists think that they are dried-up beds of long-gone rivers that once carried rainfall on Mars from the mountains down into the valleys. Runoff channels on Mars speak of a time 4 billion years ago (the age of the Martian highlands), when the atmosphere was thicker, the surface warmer, and liquid water widespread.
Outflow channels are probably relics of catastrophic flooding on Mars long ago. They appear only in equatorial regions and generally do not form extensive interconnected networks. Instead, they are probably the paths taken by huge volumes of water draining from the southern highlands into the northern plains. The onrushing water arising from these flash floods likely also formed the odd teardrop-shaped “islands” (resembling the miniature versions seen in the wet sand of our beaches at low tide) that have been found on the plains close to the ends of the outflow channels. Judging from the width and depth of the channels, the flow rates must have been truly enormous―perhaps as much as a hundred times greater than the 105 tons per second carried by the great Amazon river. Flooding shaped the outflow channels approximately 3 billion years ago, about the same times as the northern volcanic plains formed.
Some scientists speculate that Mars may have enjoyed an extended early Period during which rivers, lakes, and perhaps even oceans adorned its surface. A 2003 Mars Global Surveyor image shows what mission specialists think may be a delta―a fan-shaped network of channels and sediments where a river once flowed into a larger body of water, in this case a lake filling a crater in the southern highlands. Other researchers go even further, suggesting that the data provide evidence for large open expenses of water on the early Martian surface. A computer-generated view of the Martian north polar region shows the extent of what may have been an ancient ocean covering much of the northern lowlands. The Hellas Basin, which measures some 3,000 kilometers across and has a floor that lies nearly 9 kilometers below the basin’s rim, is another candidate for an ancient Martian sea.
These ideas remain controversial. Proponents point to features such as the terraced “beaches” shown in one image, which could conceivably have been left behind as a lake or ocean evaporated and the shoreline receded. But detractors maintain that the terraces could also have been created by geological activity, perhaps related to the geologic forces that depressed the Northern Hemisphere far below the level of the south, in which case they have nothing whatever to do with Martian water. Furthermore, Mars Global Surveyor data released in 2003 seem to indicate that the Martian surface contains too few carbonate rock layers―layers containing compounds of carbon and oxygen―that should have been formed in abundance in an ancient ocean. Their absence supports the picture of a cold, dry Mars that never experienced the extended mild period required to form lakes and oceans. However, more recent data imply that at least some parts of the planet did in fact experience long periods in the past during which liquid water existed on the surface.
Aside from some small-scale gullies (channels) found since 2000, which are inconclusive, astronomers have no direct evidence for liquid water anywhere on the surface of Mars today, and the amount of water vapor in the Martian atmosphere is tiny. Yet even setting aside the unproven hints of ancient oceans, the extent of the outflow channels suggests that a huge total volume of water existed on Mars in the past. Where did all the water go? The answer may be that virtually all the water on Mars is now locked in the permafrost layer under the surface, with more contained in the planet’s polar caps.
Paragraph 1 Photographic evidence suggests that liquid water once existed in great quantity on the surface of Mars. Two types of flow features are seen: runoff channels and outflow channels. Runoff channels are found in the southern highlands. These flow features are extensive systems―sometimes hundreds of kilometers in total length―of interconnecting, twisting channels that seem to merge into larger, wider channels. They bear a strong resemblance to river systems on Earth, and geologists think that they are dried-up beds of long-gone rivers that once carried rainfall on Mars from the mountains down into the valleys. Runoff channels on Mars speak of a time 4 billion years ago (the age of the Martian highlands), when the atmosphere was thicker, the surface warmer, and liquid water widespread.
1. The word merge in the passage is closest in meaning to
2. What does the discussion in paragraph 1 of runoff channels in the southern highlands suggest about Mars?
○The atmosphere of Mars was once thinner than it is today.
○Large amounts of rain once fell on parts of Mars.
○The river systems of Mars were once more extensive than Earth’s.
○The rivers of Mars began to dry up about 4 billion years ago.
Paragraph 2 Outflow channels are probably relics of catastrophic flooding on Mars long ago. They appear only in equatorial regions and generally do not form extensive interconnected networks. Instead, they are probably the paths taken by huge volumes of water draining from the southern highlands into the northern plains. The onrushing water arising from these flash floods likely also formed the odd teardrop-shaped “islands” (resembling the miniature versions seen in the wet sand of our beaches at low tide) that have been found on the plains close to the ends of the outflow channels. Judging from the width and depth of the channels, the flow rates must have been truly enormous―perhaps as much as a hundred times greater than the 105 tons per second carried by the great Amazon river. Flooding shaped the outflow channels approximately 3 billion years ago, about the same times as the northern volcanic plains formed.
3. The word relics in the passage is closest in meaning to
4. The word miniature in the passage is closest in meaning to
5. In paragraph 2, why does the author include the information that 105 tons of water flow through the Amazon river per second?
○To emphasize the great size of the volume of water that seems to have flowed through Mars’ outflow channels
○To indicate data used by scientists to estimate how long ago Mars’ outflow channels were formed
○To argue that flash floods on Mars may have been powerful enough to cause tear-shaped “islands” to form
○To argue that the force of flood waters on Mars was powerful enough to shape the northern volcanic plains
6. According to paragraph 2, all of the following are true of the outflow channels on Mars EXCEPT:
○They formed at around the same time that volcanic activity was occurring on the northern plains.
○They are found only on certain parts of the Martian surface.
○They sometimes empty onto what appear to have once been the wet sands of tidal beaches.
○They are thought to have carried water northward from the equatorial regions.
Paragraph 3 Some scientists speculate that Mars may have enjoyed an extended early Period during which rivers, lakes, and perhaps even oceans adorned its surface. A 2003 Mars Global Surveyor image shows what mission specialists think may be a delta―a fan-shaped network of channels and sediments where a river once flowed into a larger body of water, in this case a lake filling a crater in the southern highlands. Other researchers go even further, suggesting that the data provide evidence for large open expenses of water on the early Martian surface. A computer-generated view of the Martian north polar region shows the extent of what may have been an ancient ocean covering much of the northern lowlands. The Hellas Basin, which measures some 3,000 kilometers across and has a floor that lies nearly 9 kilometers below the basin’s rim, is another candidate for an ancient Martian sea.
7. All of the following questions about geological features on Mars are answered in paragraph 3 EXCEPT:
○What are some regions of Mars that may have once been covered with an ocean?
○Where do mission scientists believe that the river forming the delta emptied?
○Approximately how many craters on Mars do mission scientists believe may once have been lakes filled with water?
○During what period of Mars’ history do some scientists think it may have had large bodies of water?
8. According to paragraph 3, images of Mars’ surface have been interpreted as support for the idea that
○the polar regions of Mars were once more extensive than they are now
○a large part of the northern lowlands may once have been under water
○deltas were once a common feature of the Martian landscape
○the shape of the Hellas Basin has changed considerably over time
Paragraph 4 These ideas remain controversial. Proponents point to features such as the terraced “beaches” shown in one image, which could conceivably have been left behind as a lake or ocean evaporated and the shoreline receded. But detractors maintain that the terraces could also have been created by geological activity, perhaps related to the geologic forces that depressed the Northern Hemisphere far below the level of the south, in which case they have nothing whatever to do with Martian water. Furthermore, Mars Global Surveyor data released in 2003 seem to indicate that the Martian surface contains too few carbonate rock layers―layers containing compounds of carbon and oxygen―that should have been formed in abundance in an ancient ocean. Their absence supports the picture of a cold, dry Mars that never experienced the extended mild period required to form lakes and oceans. However, more recent data imply that at least some parts of the planet did in fact experience long periods in the past during which liquid water existed on the surface.
9. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
○But detractors argue that geological activity may be responsible for the water associated with the terraces.
○But detractors argue that the terraces may have been formed by geological activity rather than by the presence of water.
○But detractors argue that the terraces may be related to geological forces in the Northern Hemisphere of Mars, rather than to Martian water in the south.
○But detractors argue that geological forces depressed the Northern Hemisphere so far below the level of the south that the terraces could not have been formed by water.
10. According to paragraph 4, what do the 2003 Global Surveyor data suggest About Mars?
○Ancient oceans on Mars contained only small amounts of carbon.
○The climate of Mars may not have been suitable for the formation of large bodies of water.
○Liquid water may have existed on some parts of Mars’ surface for long periods of time.
○The ancient oceans that formed on Mars dried up during periods of cold, dry weather.
Paragraph 5 Aside from some small-scale gullies (channels) found since2000, which are inconclusive, astronomers have no direct evidence for liquid water anywhere on the surface of Mars today, and the amount of water vapor in the Martian atmosphere is tiny. Yet even setting aside the unproven hints of ancient oceans, the extent of the past. Where did all the water go? The answer may be that virtually all the water on Mars is now locked in the permafrost layer under the surface, with more contained in the planet’s polar caps.
11. The word hints in the passage is closest in meaning to
Paragraph 2 Outflow channels are probably relics of catastrophic flooding on Mars long ago. ■They appear only in equatorial regions and generally do not form extensive interconnected networks. ■Instead, they are probably the paths taken by huge volumes of water draining from the southern highlands into the northern plains. ■The onrushing water arising from these flash floods likely also formed the odd teardrop-shaped “islands” (resembling the miniature versions seen in the wet sand of our beaches at low tide) that have been found on the plains close to the ends of the outflow channels. ■Judging from the width and depth of the channels, the flow rates must have been truly enormous―perhaps as much as a hundred times greater than the 105 tons per second carried by the great Amazon river. Flooding shaped the outflow channels approximately 3 billion years ago, about the same times as the northern volcanic plains formed.
12. Look at the four squares [■] that indicate where the following sentence could be added to the passage.
These landscape features differ from runoff channels in a number of ways.
Where would the sentence best fit?
13. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.
There is much debate concerning whether Mars once had water.
1. Mars’ runoff and outflow channels are large-scale, distinctive features that suggest that large quantities of liquid water once flowed on Mars.
2. Although some researchers claim that Mars may once have had oceans, others dispute this, pointing to an absence of evidence or offering alternative interpretations of evidence.
3. Various types of images have been used to demonstrate that most of Martian surface contains evidence of flowing water.
4. The runoff and outflow channels of Mars apparently carried a higher volume of water and formed more extensive networks than do Earth’s river systems.
5. There is very little evidence of liquid water on Mars today, and it is assumed that all the water that once existed on the planet is frozen beneath its surface.
6. While numerous gullies have been discovered on Mars since 2000, many astronomers dismiss them as evidence that Mars once had liquid water.
The Development of Printing
The Development of Printing
Printing with movable type, a revolutionary departure from the old practice of copying by hand, was invented in the 1440s by Johannes Gutenberg, a German goldsmith. Mass production of identical books and pamphlets made the world of letters more accessible to a literate audience. Two preconditions proved essential for the advent of printing: the industrial production of paper and the commercial production of manuscripts.
Increased paper production in the fourteenth and fifteenth centuries was the first stage in the rapid growth of manuscript books—hand-copied works bound as books—which in turn led to the invention of mechanical printing. Papermaking came to Europe from China via Arab intermediaries. By the fourteenth century, paper mills were operating in Italy, producing paper that was much more fragile but much cheaper than parchment or vellum, animal skins that Europeans had previously used for writing. To produce paper, old rags were soaked in a chemical solution, beaten by mallets into a pulp, washed with water, treated, and dried in sheets—a method that still produces good-quality paper today.
By the fifteenth century, a brisk industry in manuscript books was flourishing in Europe’s university towns and major cities. Production was in the hands of merchants called stationers, who supplied materials, arranged contracts for book production, and organized workshops known as scriptoria, where the manuscripts were copied, and acted as retail booksellers. The largest stationers, in Paris and Florence, were extensive operations by fifteenth-century standards. The Florentine Vespasiano da Bisticci, for example, created a library for Cosimo de’ Medici, the head of Florence’s leading family, by employing 45 copyists to complete 200 volumes in 22 months. Nonetheless, bookmaking in scriptoria was slow and expensive.
The invention of movable type was an enormous technological breakthrough that took bookmaking out of the hands of human copyists. Printing was not new: the Chinese had been printing by woodblock since the tenth century, and woodcut pictures (in which an image is cut on wood and then transferred to paper) made their appearance in Europe in the early fifteenth century. Movable type, however, allowed entire manuscripts to be printed. The process involved casting durable metal molds to represent the letters of the alphabet. The letters were arranged to represent the text on a page and then pressed in ink against a sheet of paper. The imprint could be repeated numerous times with only a small amount of human labor. In 1467 two German printers established the first press in Rome and produced 12,000 volumes in five years, a feat that in the past would have required one thousand scribes working full time for the same number of years.
After the 1440s, printing spread rapidly from Germany to other European countries. The cities of Cologne, Strasbourg, Nuremberg, Basel, and Augsburg had major presses, many Italian cities had established their own by 1480. In the 1490s, the German city of Frankfurt became an international meeting place for printers and booksellers. The Frankfurt book fair, where printers from different nations exhibited their newest titles, represented a major international cultural event and remains an unbroken tradition to this day. Early books from other presses were still rather exclusive and inaccessible, especially to a largely illiterate population. Perhaps the most famous early book, Gutenberg’s two-volume edition of the Latin Bible, was unmistakably a luxury item. Altogether 185 copies were printed. First priced at well over what a fifteenth-century professor could earn in a year, the Gutenberg Bible has always been one of the most expensive books in history, both for its rarity and its exquisite crafting.
Some historians argue that the invention of mechanical printing gave rise to a communications revolution as significant as, for example, the widespread use of the personal computer today. The multiplication of standardized texts altered the thinking habits of Europeans by freeing individuals from having to memorize everything they learned; it certainly made possible the speedy and inexpensive dissemination of knowledge. It created a wilder community of scholars, no longer dependent on personal patronage or church sponsorship for texts. Printing facilitated the free expression and exchange of ideas, and its disruptive potential did not go unnoticed by political and church authorities. Emperors and bishops in Germany, the homeland of the printing industry, moved quickly to issue censorship regulations.
1. The word "advent" in the passage is closet in meaning to
2. In describing the paper produced by Italian paper mills in the fourteenth century as comparatively "fragile" the author means that this paper was
A. variable in quality
B. limited in how it could be used
C. easily damaged
D. dark in color
3. According to paragraph 2, which of the following is true of papermaking?
A. In fourteenth- and fifteenth-century Europe, it was restricted to Italy, which was the only country with the technology to build paper mills.
B. It was brought to Europe from China.
C. Its development ended the practice of copying books by hand.
D. It produces a superior writing material that is stronger than parchment.
4. Which of the following can be inferred from paragraph 2 about the process of making paper in fourteenth- and fifteenth-century Europe?
A. It was based on the process previously used to make parchment and vellum.
B. It was replaced by a process that added steps to create a better quality of paper.
C. It was dependent on the availability of discarded or used cloth.
D. It produced paper that was more fragile than paper made in China.
5. The author mentions "Vespasiano da Bisticci" in order to emphasize
A. the process by which stationers obtained the necessary materials for book production
B. the equal importance of Florence and Paris in the rapidly developing book industry
C. the superiority of Florentine libraries to those in other European cities
D. that making books was a commercial enterprise in Europe before the invention of printing
6. All of the following were mentioned in paragraph 3 as functions of stationers in fifteenth-century Europe EXCEPT
A. the creation of contracts for production of books
B. the provision of materials for copying books
C. the hiring of authors to compose new books
D. the organization of scriptoria
7. The word "durable" in the passage is closet in meaning to
C. long lasting
8. According to paragraph 4, which of the following occurred because of the invention of movable type?
A. An increase in the cost of book production
B. An increase in the popularity of the techniques of woodblock and woodcut
C. The creation of a large number of printing jobs
D. A decline in the importance of human copyists
9. Which of the following can be inferred from paragraph 5 about the Gutenberg Bible?
A. It was printed in Frankfurt.
B. People with average incomes were not likely to own it.
C. Numerous copies of it were sold at the Frankfurt book fair.
D. It was one of the first expensive books to be sold to an international population.
10. The author mentions "the personal computer" in the passage in order to
A. compare the importance of the development of mechanical printing to the development of the computer
B. contrast the superiority of communications technology in the modern era to that of the fifteenth century
C. emphasize the sophisticated social and economic growth of fifteenth-century society
D. emphasize the conflicting views of historians about the significance of new technologies
11. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaningin important ways of leave out essential information.
A. European ways of thinking were affected by the new multiple sources of knowledge that became available through the standardization of texts.
B. Once standardized texts became widespread, people could acquire knowledge in faster, more affordable ways because they no longer had to memorize texts.
C. Individuals were increasingly free to take advantage of the large number of standardized texts that became available.
D. It became easier for people to increase their knowledge in many areas because books were significantly cheaper than they had previously been.
12. The word "facilitated" in the passage is closet in meaning to
C. made easier
13. For such leaders, the uncontrolled expression of ideas was clearly unwelcome.
A. The multiplication of standardized@1@4
B. It created a wilder community of scholars@1@4
C. Printing facilitated the free expression@1@4
D. Emperors and bishops in Germany@1@4
14. The invention of printing was a revolutionary development that brought about profound social change in Europe in the fourteenth and fifteenth centuries.
A. Printing with metal type rather than woodblocks was the invention of a German goldsmith living in Rome, the center of printing in the fifteenth century.
B. A precondition for the successful production and distribution of mechanically printed books was the earlier commercial organization of hand-copied book production by merchants known as stationers.
C. Because movable type made it more economical to produce many copies of a single book, the invention of mechanical printing had an immense effect on the spread of knowledge.
D. The expansion of the paper making industry in the fourteenth and fifteenth centuries made it possible to fully and economically use the invention of movable type in book production.
E. In the fifteenth century, printed books were internationally distributed through the Frankfurt book fair, although few people in the fifteenth century could afford books or were able to read them.
F. The most important and expensive early mechanically printed book was Gutenberg’s two-volume Latin Bible, produced in an edition of only 185 copies.
Heat Dissipation Behavior of Birds
首段总述当鸟类热的时候，会通过不同方式来散热，主要是feather，blood and evaporation.
Temperature Regulation in Marine Organisms
There are two extremes of temperature regulation in organisms. Homeotherms are organisms that regulate body temperature to a constant level, usually above that of the ambient (surrounding) environment. A constant and relatively high body temperature enables biochemical reactions to occur in a relatively constant internal environment and at a relatively high rate. Most birds have a body temperature of about 40℃, whereas the temperature of most marine mammals is about 38℃. Because such temperatures are much higher than that of most seawater, marine homeotherms lose heat rapidly to the surrounding environment.
There is another completely different style of living. Poikilotherms are organisms whose body temperature conforms to that of the ambient environment. All subtidal marine invertebrates and most fishes fit into this category. There is an interesting intermediate status in which body temperature is usually somewhat higher than ambient temperature. Strong-swimming fishes, such as skipjack tuna and yellowfin tuna, have this intermediate status. Their rise in temperature above ambient conditions stems from metabolic heat generated by muscular activity (swimming) combined with a heat retention mechanism. The temperature rise is probably necessary to generate the increased biochemical reaction rates that are needed for sustained activity. In contrast, some intertidal animals are not true Poikilotherms, they maintain themselves at lower-than-ambient body temperature, using both evaporation and circulation of body fluids to avoid being heated at low tide by the Sun. Their body temperatures, therefore, differ from that of an inanimate object of the same size and shape that might be placed on the shore. Intertidal organisms absorb and lose heat directly to the air. Darker-colored forms can absorb more heat than can light-colored forms, therefore, variation in color can reflect differences in adaptation to the capture of solar energy at different latitudes.
Ocean temperatures are usually less than 27℃ and may be less than 0℃ in some locations and during some seasons. Therefore, most homeothermic mammals and birds must lose heat continuously to the environment. Their skin is the main pathway of heat loss, especially by direct conduct of heat from the skin to the contacting colder water. Because animals have a circulatory system, heat loss from the body surface also occurs as warm interior blood is transferred and moves into contact with the periphery of the body. Their bodies also radiate heat, usually in the infrared part of the spectrum. Finally, as animals exhale, the resulting evaporation of water involves a considerable loss of heat.
The first line of defense against heat loss is a well-insulated body surface. Marine birds deal with this problem by means of specially adapted feathers. A series of interlocking contour feathers encloses a thick layer of down feathers that traps stationary air, which in turn acts as an insulating layer. Whales, porpoises, and seals are insulated against the lower sea temperatures by a thick layer of subcutaneous fat. Sea otters lack such a layer, but they constantly preen and fluff up a relatively thick layer of fur. Such mechanisms are only partly successful, however, and to generate more body heat to maintain a constant temperature, marine mammals usually must have a higher metabolic rate than similarly sized terrestrial (land) animals.
In marine mammals that have limbs, the limbs are the principal sources of heat loss because they expose a relatively greater amount of body surface area per unit volume to cold water. However, warm arterial blood must be supplied to limbs, such as the flipper of a porpoise. Heat loss in porpoises is minimized by a countercurrent heat exchanger. The arteries are surrounded by veins, within which blood is returning to the core of the animal. At any contact point, the artery, which is on the inside, is warmer than a surrounding vein, so heat is lost to the returning venous blood flow. Heat is thus reabsorbed and returned to the porpoise’s body core. This spatial relationship of circulatory vessels minimizes heat loss to the flipper and thence to the water. Although the anatomical details are quite different, fishes such as skipjack tuna have a circulatory anatomy based on the same overall design. Arteries and veins in the near-surface musculature are in contact, and in arteries and veins, respectively, blood flows in opposite directions.
1. The word "sustained" in the passage is closest in meaning to
2. According to paragraph 2, the body temperature of strong-swimming fishes is usually above that of their surroundings probably so they can
A. generate heat to warm themselves in cold waters
B. have enough energy for prolonged activity
C. generate metabolic heat for muscular activity
D. retain heat for later use when the surrounding conditions change
3. According to paragraph 2, some intertidal animals are not considered true poikilotherms because they
A. can change color and therefore the amount of heat that is absorbed
B. keep their body temperature lower than that of the ambient environment
C. use various techniques to lower their body temperature when overheated by the Sun
D. match their body temperature directly with the air temperature
4. The word "considerable" in the passage is closest in meaning to
5. According to paragraph 3, all of the following contribute to heat loss in homeothermic animals EXCEPT
A. heat transfer from the skin to the water
B. the movement of blood to the animal’s periphery
C. an increase in their activity during certain seasons
D. the evaporation of water during breathing
6. The word "stationary" in the passage is closest in meaning to
7. All of the following are mentioned in paragraph 4 as defenses against heat loss EXCEPT
A. subcutaneous fat
B. layers of feathers
C. a thick layer of fur
D. constant metabolic rates
8. What can be inferred from the comparison of terrestrial animals to marine animals in the last sentence of paragraph 4?
A. An animal’s size is not the only factor affecting its metabolic rate.
B. An animal’s size determines what mechanism can be successfully used to prevent heat loss.
C. Smaller animals are more successful than larger ones at preventing heat loss.
D. Terrestrial animals have a wider variety of mechanisms for preventing heat loss than marine animals do.
9. Paragraph 4 expands on paragraph 3 by
A. presenting various reasons why first-time defenses are inadequate to deal with the problem described in paragraph 3
B. discussing mechanisms that marine animals use to reduce the problem described in paragraph 3
C. identifying specific ways that the problem described in paragraph 3 harms marine animals
D. explaining why the problem described in paragraph 3 harms some marine animals more than others
10. The word "overall" in the passage is closest in meaning to
11. According to paragraph 5, some marine mammals that have limbs minimize heat loss by using a system in which
A. vessels that return blood to the animal’s core absorb heat from warm interior arteries
B. blood returning to the core is warmer than blood flowing from the core
C. the placement of the arteries reduces blood flow to the veins
D. both arteries and veins are in contact with near-surface musculature
12. Why does the author discuss "fishes such as skipjack tuna"?
A. To explain by contrast why the circulatory anatomy of porpoises is efficient
B. To show that marine animals other than mammals use a countercurrent exchange system to minimize heat loss
C. To identify and illustrate a type of circulatory anatomy that is common in fishes
D. To provide evidence that the amount of heat marine animals lose increases with increased body surface area
13. However, not all marine organisms can be easily classified as either homeotherms or poikilotherms.
A. Poikilotherms are organisms whose body temperature@1@4
B. All subtidal marine invertebrates and most@1@4
C. There is an interesting intermediate status@1@4
D. usually somewhat higher than ambient temperature.@2@4
14. Marine and other organisms are classified as homeotherms if they maintain a constant body temperature and as poikilotherms if their body temperature matches that of the environment.
A. Although strong-swimming fishes and intertidal organisms have body temperatures that are higher or lower than ambient temperatures, most fishes and subtidal marine organisms are poikilotherms.
B. There are no homeotherms in cold ocean waters because it is too difficult for homeotherms to prevent heat loss in these environments.
C. Features such as fur help reduce heat loss, but marine homeotherms require a higher metabolism than do terrestrial homeotherms of similar size to maintain a constant body temperature.
D. Some organisms are thought to have various methods of heat regulation in order to maintain different body temperatures at different times of year.
E. Marine homeotherms lose heat to the environment through respiration and other means, the most important being skin contact with colder seawater.
F. Animals with limbs are at a disadvantage regarding body temperature because their circulatory anatomy is poorly designed for managing heat loss.
habit & inciting cues
Task 1 二选一/偏爱
Do you agree or disagree with the following statement? Because of the increasing popularity of entertainment technology, fewer people are taking the time to read books for pleasure.
As far as I am concerned, people spend time on entertainment technology all day long. With the popularity of the high-tech, everybody got a phone, lap top or tablet computer. But it doesn’t mean that they will read fewer books. Books can be formed in different ways. Such as audio books that people can listen to it again and again, E-book that people are able to share information by having a screen shot. What is more, nowadays there are so many good videos that people upload online, they are all free educational resources that people can use in order to be knowledgeable. In a word, even though people spend time on electronic devises everyday, but they didn’t spend all of their time to relax. On the contrary, they read books in a different way.
1. 虽然很多人开车，还是有很多人需要坐火车 ，假期的时候火车更便宜
阅读分论点二：作为冰室储冰 a house for ice storage
阅读分论点三：储存粮食 to store crops
Both reading and listening talks about the application of stone chambers in the relics. To begin with, according to the reading, the chambers are used for farming sheep, yet the profession in the
listening casts doubt by making the statement that it was not possible since the chamber is dark and sheep ranges over a much larger area than the chamber. Second, the reading points out the fact that the chamber could be a house for ice storage. Yet the listening part explains that this would not be possible since the chamber did not have two walls to insulate the heat and the ice would be melted.
At last, the reading passage presents that the chamber might be used as the warehouse to store crops. However, the listening makes it clear that there were always floods in Springs and the chamber was not equipped with flood drains.
Foods and drinks that contain high levels of sugar, salt, or fats have harmful health effects when consumed in great quantities. Some people believe that governments should make these unhealthy foods and drinks more expensive by taxing them. The tax (money paid to the government) would discourage consumption of unhealthy foods and drinks and raise money for future health-care costs. Other people believe that consumers buying foods and drinks should not pay any additional tax, even if the foods or drinks are unhealthy.
Which viewpoint do you agree with, and why?
观点：neither one is good，being flexible
When burgers and chips are to feed people whose food budget is tight, they should remain at the current low prices. When such food is to be some kind of a pleasure for some other people, restaurants can charge those people more money, as a matter of fact, not for the food but for the pleasure. This may be a good solution to the dispute.
This varying pricing system, depending on the increase of tax or the exemption from the additional tax, is not intended to discriminate those people who are unable to be lavish on their dietary choice, and, instead, is to ensure that sustenance is at the cost they can afford.
Nor is the varying pricing to rip off those other people who occasionally need the enjoyment that the large amounts of salt and sugar can bring. After all, if such enjoyment, which is unhealthy, is too easy, we may see people’s indulgence in it. We cannot rely on self-discipline.
So, in fairness, choosing either side may not be a good idea. Instead, it is better to be flexible in this matter.