[外语类试卷]大学英语六级模拟试卷245及答案与解析.doc

1、大学英语六级模拟试卷 245及答案与解析 一、 Part I Writing (30 minutes) 1 Directions: For this part, you are allowed 30 minutes to write a short essay entitled The Increase in the Number of Chinese Traveling Abroad, You should write at least l5O words following the outline given below: 1. 说明这一现象 2解释产生这种现象的原因 3预测未来的趋势 (

2、说明：中国游客出国旅游开始于 1997年。据统计，当年全国出境旅游的人数为520万人次，到 2006年出境旅游的人数已超过 3000万人次。 ) 二、 Part II Reading Comprehension (Skimming and Scanning) (15 minutes) Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions attached to the passage. For questions 1-4, mark：

3、Y (for YES) if the statement agrees with the information given in the passage; N (for NO) if the statement contradicts the information given in the passage; NG (for NOT GIVEN) if the information is not given in the passage. 1 Blowing Hot and Cold Climate change may be slow and uncertain, but that is

4、 no excuse for inaction. One reason why uncertainty over climate change looks to be with us for a long time is that the oceans, which absorb carbon from the atmosphere, act as a time-delay mechanism. Their massive thermal inertia means that the climate system responds only very slowly, to changes in

5、 the composition of the atmosphere. Another complication arises from the relationship between carbon dioxide (CO2), the principal greenhouse gas (GHG), and sulphur dioxide (SO2), and a common pollutant. Efforts to reduce man-made emissions of GHGs by cutting down on fossil-fuel use will reduce emiss

6、ions of both the gases. The reduction in CO2 will cut warming, but the concurrent (同时发生的 ) SO2 cut may mask that effect by contributing to the warming. There are so many such fuzzy (模糊的 ) factors ranging from aerosol particles to clouds to cosmic radiation that we are likely to see disruptions of fa

7、miliar climate patterns for many years without knowing why they are happening or what to do about them. Tom Wigley, a leading climate scientist and member of the UNs Intergovernmental Panel on Climate Change (IPCC), goes further. He argues in an excellent book published by the Aspen Institute, “US P

8、olicies on Climate Change: What Next?“, that whatever policy changes governments pursue, scientific uncertainties will “make it difficult to detect the effects of such changes, probably for many decades.“ As evidence, he points to the negligible short-to medium-term difference in temperature resulti

9、ng from an array of emission “pathways“ on which the world could choose to embark if it decided to tackle climate change. He plots various strategies for reducing GHGs that will lead in the next century to the stabilization of atmospheric concentrations of CO2 at 550 parts per million (ppm). That is

10、 roughly double the level which prevailed in pre-industrial times, and is often suggested by climate scientists as a reasonable target. But even by 2040, the temperature differences between the various options will still be tiny and certainly within the magnitude of natural climatic variance. In sho

11、rt, in another four decades we will probably still not know if we have over-or under-shot. Ignorance is not bliss However, that does not mean we know nothing. We do know, for a start, that the “greenhouse effect“ is real: without the heat-trapping effect of water vapor, CO2, methane and other natura

12、lly occurring GHGs, our planet would be a lifeless 30 or so colder. Some of these GHG emissions are captured and stored by “sinks“, such as the oceans, forests and agricultural land, as part of natures carbon cycle. We also know that since the industrial revolution began, mankinds actions have contr

13、ibuted significantly to that greenhouse effect. Atmospheric concentrations of GHGs have risen from around 280ppm two centuries ago to around 370ppm today, thanks chiefly to mankinds use of fossil fuels and, to a lesser degree, to deforestation and other land-use changes. Both surface temperatures an

14、d sea levels have been rising for some time. There are good reasons to think temperatures will continue rising. The IPCC has estimated a likely range for that increase of 1.4 -5.8 over the next century, although the lower end of that range is more likely. Since what matters is not just the absolute

15、temperature level but the rate of change as well, it makes sense to try to slow down the increase. The worry is that a rapid rise in temperatures would lead to climate changes that could be devastating for many (though not all) parts of the world. Central America, most of Africa, much of south Asia

16、and northern China could all be hit by droughts, storms and floods and otherwise made miserable. The colder parts of the world may benefit from warming, but they too face danger. One is the conceivable collapse of the Atlantic “conveyor belt“, a system of currents that gives much of Europe its relat

17、ively mild climate; if temperatures climb too high, say scientists, the system may undergo radical changes that damage both Europe and America. That points to the biggest fear: warming may trigger irreversible changes that transform the earth into a largely uninhabitable environment. Given that poss

18、ibility, extremely remote though it is, it is no comfort to know that any attempts to stabilize atmospheric concentrations of GHGs at a particular level will take a very long time. Because of the oceans thermal inertia, explains Mr. Wigley, even once atmospheric concentrations of GHGs are stabilized

19、, it will take decades or centuries for the climate to follow suit. And even then the sea level will continue to rise. This is a vast challenge, and it is worth bearing in mind that mankinds contribution to warming is the only factor that can be controlled. So the sooner we start drawing up a long-t

20、erm strategy for climate change, the better. A low-carbon world That is why the long-term objective for climate policy must be a transition to a low-carbon energy system. Such a transition can be very gradual and need not necessarily lead to a world powered only by bicycles and windmills, for two re

21、asons that are often overlooked. One involves the precise form in which the carbon in the ground is distributed. According to Michael Grubb of the Carbon Trust, a British quasi-governmental body, the long-term problem is coal. In theory, we can burn all of the conventional oil and natural gas in the

22、 ground and still meet the most ambitious goals for tackling climate change. If we do that, we must ensure that the far greater amounts of carbon trapped as coal (and unconventional resources like tar sands) never enter the atmosphere. The other reason, as scientists took care to point out, is that

23、it is net emissions of CO2 that need to peak and decline. That leaves scope for the continued use of fossil fuels as the main source of modern energy if only some magical way can be found to capture and dispose of the associated CO2. Happily, scientists already have some magic in the works. Miracles

24、 sometimes happen Two decades ago, the world faced a similar dilemma: evidence of a hole in the ozone layer. Some inconclusive signs suggested that it was man-made, caused by the use of chlorofluorocarbons (CFCs). There was the distant threat of disaster, and the knowledge that a concerted global re

25、sponse was required. Industry was reluctant at first, yet with leadership from Britain and America the Montreal Protocol was signed in 1987. That deal has proved surprisingly successful. The manufacture of CFCs is nearly phased out, and there are already signs that the ozone layer is on the way to r

26、ecovery. This story holds several lessons for the admittedly far more complex climate problem. First, it is the rich world which has caused the problem and which must lead the way in solving it. Second, the poor world must agree to help, but is right to insist on being given time as well as money an

27、d technology to help it adjust. Third, industry holds the key: in the ozone-depletion story, it was only after DuPont and ICI broke ranks with the rest of the CFC manufacturers their a deal became possible. The final lesson is the most important: that the uncertainty surrounding a threat such as cli

28、mate change is no excuse for inaction. New scientific evidence shows that the threat from ozone depletion had been much deadlier than was thought at the time when the world decided to act. 2 The reduction of greenhouse gas by cutting down fossil-fuel use will finally delay the global warming. （ A） Y

29、 （ B） N （ C） NG 3 In recent years, scientists have reported that some uncertain factors disrupt the climate change. （ A） Y （ B） N （ C） NG 4 Scientists hope that by 2040 the temperature will still be stable by the cooperation among some countries. （ A） Y （ B） N （ C） NG 5 We know that since Industrial

30、 Revolution humans caused the greenhouse effect greatly, thus making the temperature rising. （ A） Y （ B） N （ C） NG 6 Over the next century the temperature will be more likely to rise from _ according to the estimation of IPCC. 7 The rapid rise in temperature will lead to climate changes which finall

31、y in turn will _ in the long run. 8 Theoretically, people can burn all of the conventional natural resources and can still realize the great goals of _. 9 If a good way can be found to trap and dispose of the associated CO2, there is the possibility of continuing to use fossil fuels as _. 10 Accordi

32、ng to the Montreal Protocol, the production of CFCs almost stopped, and there are already signs that the ozone layer is _. 11 New scientific data prove that _ have been much more devastating than people thought at the time when they decided to take action. Section A Directions: In this section, you

33、will hear 8 short conversations and 2 long conversations. At the end of each conversation, one or more questions will be asked about what was said. Both the conversation and the questions will be spoken only once. After each question there will be a pause. During the pause, you must read the four ch

34、oices marked A, B, C and D, and decide which is the best answer. （ A） In a grocery store. （ B） Over the telephone. （ C） At a party. （ D） In Marys house. （ A） Theyre happy Marias playing it again. （ B） They are both very tired of it. （ C） The man likes to listen to it often. （ D） The woman has never

35、heard it before. （ A） In a supermarket. （ B） In an advertising agency. （ C） At a police station. （ D） In a customs office. （ A） An annoyance call. （ B） A crossword puzzle. （ C） A broken telephone. （ D） A musical instrument. （ A） 30 minutes. （ B） 50 minutes. （ C） 70 minutes. （ D） 80 minutes. （ A） On

36、Wednesday. （ B） On Thursday. （ C） On Friday. （ D） On Monday. （ A） Hell have a weekend party at home. （ B） Hell come to an English party at his friends house. （ C） Hell go to meet someone at the airport. （ D） Hell make arrangements to meet foreign friends. （ A） They wont be able to set up an automobi

37、le company. （ B） They wont be able to come to the opening ceremony. （ C） They shouldnt have accepted the invitation. （ D） They shouldnt inform them in advance. （ A） College professors. （ B） Computer users. （ C） Lonely people. （ D） Internet surfers. （ A） Suffering poor health. （ B） Causing anxiety. （

38、 C） Becoming aggressive. （ D） Destroying personal contact. （ A） Joining a club. （ B） Using a timer. （ C） Putting the computer in the living room. （ D） Not spending hours uninterruptedly. （ A） Economical fuel. （ B） A new kind of fuel. （ C） Energy saving. （ D） Air pollution. （ A） Hes preparing for a t

39、est. （ B） He lost his notes. （ C） He missed the class. （ D） Hes studying this subject. （ A） It will reduce the amount of pollutants in the air. （ B） It will increase the amount of unpleasant odors from vehicles. （ C） It will eventually destroy the ozone layer. （ D） It will reduce the cost of running

40、 large vehicles. （ A） Its expensive to manufacture. （ B） it hasnt been adequately tested. （ C） It damages car engines. （ D） its dangerous to transport. Section B Directions: In this section, you will hear 3 short passages. At the end of each passage, you will hear some questions. Both the passage an

41、d the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A, B, C and D. （ A） To keep their food clean. （ B） To imitate the people of the East. （ C） To impress visitors with their good manners. （ D） To amuse the English. （ A） We

42、ll-mannered. （ B） Nice. （ C） Woman-like or showing off. （ D） Ill-mannered. （ A） At the same time as in Italy. （ B） In the 15th century. （ C） About 600 years after forks came to Europe. （ D） In the 11th century. （ A） Planets. （ B） The moon. （ C） The sun. （ D） Gods. （ A） Twelve lunar months. （ B） The

43、home of the moon goddess. （ C） A mentally ill person affected by the moon. （ D） A guard against the moon. （ A） The Gods of Rome. （ B） Ancient Beliefs. （ C） The Rhythm of the Universe. （ D） Gods in Our Words. （ A） Because it changes color in a regular 24-hour rhythm. （ B） Because it changes color in

44、response to the suns rays. （ C） Because it constantly changes color. （ D） Because it changes color every hour. （ A） To tell the crab what time it is. （ B） To protect the crab from the sunlight and enemies. （ C） To keep the crab warm. （ D） To be of no real use. （ A） They change color every 50 minutes

45、. （ B） They change color more quickly. （ C） They change color more slowly. （ D） They change color on the same schedule. （ A） The Rhythmic Cycle of the Sun and the Tide （ B） Discoveries in Biology （ C） A Scientific Study （ D） A Living Clock Section C Directions: In this section, you will hear a passa

46、ge three times. When the passage is read for the first time, you should listen carefully for its general idea. When the passage is read for the second time, you are required to fill in the blanks numbered from 36 to 43 with the exact words you have just heard. For blanks numbered from 44 to 46 you a

47、re required to fill in the missing information. For these blanks, you can either use the exact words you have just heard or write down the 36 Why does cream go bad faster than butter? Some researchers think that it comes down to the structure of the food, not its chemical【 B1】 _ -a finding that coul

48、d help rid some processed foods of chemical preservatives. Cream and butter contain much the same【 B2】 _ , so why cream should sour much faster has been a【 B3】 _ . Both are emulsions-tiny globules of one liquid evenly【 B4】 _ throughout another. The difference lies in whats in the globules and whats

49、in the surrounding. In cream, fatty globules drift about in a sea of water. In butter, globules of a watery【 B5】 _ are locked away in a sea of fat. The bacteria which make the food go bad prefer to live in the watery regions of the【 B6】 _ . This means that in cream, the bacteria are free to grow throughout the mixture. When the situation is【 B7】 _ , the bacteria are locked away in【 B8】 _ buried deep in the sea of fat.【 B9】 _ . They