[外语类试卷]大学英语六级模拟试卷654及答案与解析.doc

1、大学英语六级模拟试卷 654及答案与解析 一、 Part I Writing (30 minutes) 1 For this part, you are allowed 30 minutes to write a short essay entitled Should Retirement Age Be Raised? You should write at least 150 words according to the outline given below. 1有人赞成提高退休年龄 2有人则反对 3你的看法 Should Retirement Age Be Raised? 二、 Part

2、 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： Y (for YES) if the statement agrees with the information given in the passage; N

3、 (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 Climate Change Scientists predict increasing droughts, floods and extreme weather and say there is growing evidence that human activities are to blame. Wh

4、at Is Climate Change? The planets climate is constantly changing. The global average temperature is currently in the region of 15 . Geological and other evidence suggests that, in the past, this average may have been as high as 27 and as low as 7 . But scientists are concerned that the natural fluct

5、uation (波动 ) has been overtaken by a rapid human-induced warming that has serious implications for the stability of the climate on which much life on the planet depends. What Is the “Greenhouse Effect“? The greenhouse effect refers to the role played by gases which effectively trap energy from the S

6、un in the Earths atmosphere. Without them, the planet would be too cold to sustain life as we know it. The most important of these gases in the natural greenhouse effect is water vapor, but concentrations of that are changing little and it plays almost no role in modern human-induced greenhouse warm

7、ing. Other greenhouse gases include carbon dioxide, methane (甲烷 ) and nitrous (含氮的 ) oxide, which arc released by modern industry, agriculture and the burning of fossil fuels. Their concentration in the atmosphere is increasing-the concentration of carbon dioxide has risen by more than 30% since 180

8、0. The majority of climate scientists accept the theory that an increase in these gases will cause a rise in the Earths temperature. What Is the Evidence of Warming? Temperature records go back to the late 19th century and show that the global average temperature increased by about 0.6 in the 20th c

9、entury. Sea levels have risen 10 20 cm-thought to be caused mainly by the expansion of warming oceans. Most glaciers in temperate regions of the world and along the Antarctic Peninsula are in retreat, and records show Arctic sea-ice has thinned by 40% in recent decades in summer and autumn. There ar

10、e anomalies (异常 ) however-parts of the Antarctic appear to be getting colder, and there are discrepancies between trends in surface temperatures and those in the troposphere(对流层 ) (the lower portion of the atmosphere). How Much Will Temperatures Rise? If nothing is done to reduce emissions, current

11、climate models predict a global temperature increase of 1.4 5.8 by 2100. Even if we cut greenhouse gas emissions dramatically now, scientists say the effects would continue because parts of the climate system, particularly large bodies of water and ice, can take hundreds of years to respond to chang

12、es in temperature. It also takes greenhouse gases in the atmosphere decades to break down. It is possible that we have already irrevocably(不可撤回地 ) committed the Greenland ice sheet to melting, which would cause an estimated 7m rise in sea level. There are also indications that the west Antarctic ice

13、 sheet may have begun to melt, though scientists caution further research is necessary. How Will the Weather Change? Globally, we can expect more extreme weather events, with heat waves becoming hotter and more frequent. Scientists predict more rainfall overall, but say the risk of drought in inland

14、 areas during hot summers will increase. More flooding is expected from storms and rising sea levels. There are, however, likely to be very strong regional variations in these patterns, and these are difficult to predict. What Will the Effects Be? The potential impact is huge, with predicted freshwa

15、ter shortages, sweeping changes in food production conditions, and increases in deaths from floods, storms, heat waves and droughts. Poorer countries, which are least equipped to deal with rapid change, will suffer most. Plant and animal extinctions are predicted as habitats change faster than speci

16、es can adapt, and the World Health Organization has warned that the health of millions could be threatened by increases in malaria, water-borne disease and malnutrition. What Dont We Know? We dont know exactly what proportion of the observed warming is caused by human activities or what the knock-on

17、 effects of the warming will be. The precise relationship between concentrations of carbon dioxide (and other greenhouse gases) and temperature rise is not known, which is one reason why there is such uncertainty in projections Of temperature increase. Global warming will cause some changes which wi

18、ll speed up further warming, such as the release of large quantities of the greenhouse gas methane as permafrost(永久冻结带 ) melts. Other factors may mitigate(减轻 ) warming. It is possible that plants may take more carbon dioxide from the atmosphere as their growth speeds up in warmer conditions, though

19、this remains in doubt. Scientists are not sure how the complex balance between these positive and negative feedback effects will play out. What about the Skeptics? Global warming “skeptics“ fall into three broad camps: - those who maintain temperatures are not rising; - those who accept the climate

20、is changing but suspect it is largely down to natural variation; - those who accept the theory of human-induced warming but say it is not worth tackling as other global problems are more pressing. Nevertheless, there is a growing scientific consensus (舆论 ) that, even on top of the natural variabilit

21、y of the climate, something out of the ordinary is happening and humans are to blame. A scientific report commissioned by the U.S. government has concluded there is “clear evidence“ of climate change caused by human activities. The report, from the federal Climate Change Science Program, said trends

22、 seen over the last 50 years “cannot be explained by natural processes alone“. It found that temperatures have increased in the lower atmosphere as well as at the Earths surface. However, scientists involved in the report say better data is badly needed. Observations down the years have suggested th

23、at the troposphere, the lower atmosphere, is not warming up, despite evidence that temperatures at the Earths surface are rising. This goes against generally accepted tenets (原则 ) of atmospheric physics, and has been used by “climate skeptics“ as proof that there is no real warming. The new report,

24、Temperature Trends in the Lower Atmosphere, re-analyses the atmospheric data and concludes that tropospheric temperatures are rising. This means, it says, that the impact of human activities upon the global climate is clear. “The observed patterns of change over the past 50 years cannot be explained

25、 by natural processes alone, nor by the effect of short-lived atmospheric constituents (such as aerosols and tropospheric ozone ) alone,“ it says. Holes in the Data But there are some big uncertainties which still need resolving. Globally, the report concludes, tropospheric temperatures have risen b

26、y 0.10 and 0.20 per decade since 1979, when satellite data became generally available. The wide gap between the two figures means, says the report, that “.it is not clear whether the troposphere has warmed more or less than the surface.“ Peter Thorne, of the U.K. Meteorological Office, who contribut

27、ed to the report, ascribes this uncertainty to poor data “Basically, weve not been observing the atmosphere with climate in mind,“ he told the BBC News website. “Were looking for very small signals in data that are very noisy. From one day to the next, the temperature can change by 10 , but were loo

28、king for a signal in the order of 0.1 per decade.“ The report shows up a particular discrepancy concerning the tropics, where it concludes that temperatures are rising by between 0.02 and 0.19 per decade, a big margin of error. Additionally, the majority of the available datasets show more warming a

29、t the surface than in the troposphere, whereas most models predict the opposite. For Fred Singer, of the Science and Environmental Policy Project, a prominent climate skeptic, this suggests that the reports support for the concept of human-induced climate change is spin rather than substance. “The b

30、asic data in the report is quite OK,“ he said, “but the interpretation thats been given is different from what the data says.“ No Inconsistency Measuring tropospheric temperatures is far from a simple business. Satellites sense the “average“ temperature of the air between themselves and the Earth, l

31、argely blind to what is happening at different altitudes. To compound matters, instruments on board satellites degrade over time, orbits subtly drift, and calibration (校准 ) between different satellites may be poor. Weather balloons (or radiosondes) take real-time measurements as they ascend, but sci

32、entists can never assess instruments afterwards; they are “fire-and-forget“ equipment. Correcting for all these potential sources of error is a sensitive and time-consuming process. The report makes clear recommendations for the kind of infrastructure needed to produce higher-quality data and resolv

33、e remaining uncertainties. Key recommendations include: - establishing reference sites for radiosonde measurements which would increase consistency between datasets; - making sure the operating periods of satellites overlap so instruments can be cross-calibrated; -observing factors such as wind, clo

34、uds, and humidity in the troposphere to make sure they are consistent with temperature data. Such observations could produce an unambiguous picture of tropospheric warming, removing discrepancies over the scientific picture and providing better data which can be used to improve computer models. 2 In

35、 the past, the global average temperature may have been 27 . （ A） Y （ B） N （ C） NG 3 Water vapor plays almost no role in modern greenhouse warming. （ A） Y （ B） N （ C） NG 4 There are discrepancies between trends in surface temperatures and those in the troposphere in the Antarctic. （ A） Y （ B） N （ C）

36、 NG 5 It may take large bodies of water and ice decades to respond to changes in temperature. （ A） Y （ B） N （ C） NG 6 It is difficult to predict the strong regional variations in the patterns of _. 7 According to the WHO, increases in malaria, water-borne disease and malnutrition could threaten _. 8

37、 The release of large quantities of the greenhouse gas methane as permafrost melts will speed up _. 9 A U.S. scientific report concluded that some trends of climate change were caused by _. 10 Most models predict more warming in the troposphere than at the surface, whereas most datasets _. 11 To res

38、olve remaining uncertainties, its necessary to observe factors such as wind, clouds, and humidity in the troposphere to make sure they are consistent with _. Section A Directions: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, one or m

39、ore 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 choices marked A, B, C and D, and decide which is the best answer. （ A） She had a bad cold. （ B） She

40、had a car accident. （ C） She got home before 10 oclock. （ D） She was delayed. （ A） Colleagues. （ B） Husband and Wife. （ C） Friends. （ D） Roommates. （ A） At noon. （ B） In the afternoon. （ C） In the evening. （ D） In the morning. （ A） Janet. （ B） Chris. （ C） Her husband. （ D） The man who called her in

41、the evening. （ A） Yesterday morning. （ B） Yesterday noon. （ C） Yesterday afternoon. （ D） Yesterday evening. （ A） He doesnt have good qualifications. （ B） His resume hasnt outlined his past in a proper way. （ C） He is not nervous when taking an interview. （ D） He always thinks that the interviewer is

42、 like an enemy. （ A） He should outline his past better. （ B） He should send his resume directly to the manager. （ C） He should create a new area in his resume called “value offered“. （ D） He neednt write different resume to different employers. （ A） A shipping company. （ B） A consulting company. （ C

43、） An accounting company. （ D） A headhunting company. 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 and the questions will be spoken only once. After you hear a question, you must choose the best answe

44、r from the four choices marked A, B, C and D. （ A） By producing pressure waves going in the opposite direction. （ B） By mixing new sound waves with the noise and sending them out together. （ C） By mixing high-frequency sound waves with low-frequency ones. （ D） By making a copy of the unwanted sound

45、waves and letting it out a little later. （ A） It can make a car lighter. （ B） It can make a car faster. （ C） It can reduce the cost of a silencer. （ D） It can improve the performance of a silencer. （ A） It is still being tried out. （ B） People still have their doubts. （ C） It increases the cost of c

46、ar production. （ D） Carmakers are not sure if it is necessary. （ A） A detective from the Los Angeles Police Department. （ B） Detective Garcia from the New York Police Department. （ C） Someone who lives in the neighborhood. （ D） Roberts neighbor. （ A） He succeeded in beating a mugger in a fight. （ B）

47、 He became a karate(空手道 )expert. （ C） He passed away in a hospital after a fight with a mugger. （ D） He called the police after being mugged. （ A） According to the lecture, you should try to avoid dark, deserted streets at night. （ B） According to the lecture, you should give the mugger what he want

48、s and call the police as soon as he leaves. （ C） According to the lecture, its much safer for a man to put his wallet in his front pocket. （ D） According to the lecture, its safe for you to get on empty subway cars. （ A） Children. （ B） Family. （ C） Parents. （ D） ASPCA （ A） Because it is powerful and

49、 aggressive. （ B） Because its a companion and protection breed. （ C） Because most people are afraid of it. （ D） Because it is very small and easy to train. （ A） It need to be walked daily. （ B） It is an ideal hunting dog. （ C） It can exercise at home. （ D） Its hard to handle for children. （ A） The importance of dogs in our daily life. （ B） Ways to train various kinds of dogs. （ C） Methods to collect information about dogs. （ D） How to choose an ideal dog for the family. Section