大学六级模拟744及答案解析.doc

1、大学六级模拟 744 及答案解析(总分：454.50，做题时间：90 分钟)一、Part Writing(总题数：1，分数：-1.00)1.英特网的积极影响。 2英特网的消极影响。 3你的看法。 Positive and Negative Effects of Internet（分数：-1.00）_二、Part Reading Compr(总题数：2，分数：77.00)Climate Change Scientists predict increasing droughts, floods and extreme weather and say there is growing evidenc

2、e that human activities are to blame. What Is Climate Change? The planet“s 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 scientis

3、ts are concerned that the natural fluctuation (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 wh

4、ich effectively trap energy from the Sun in the Earth“s 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

5、in modern human-induced greenhouse warming. 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

6、 has risen by more than 30% since 1800. The majority of climate scientists accept the theory that an increase in these gases will cause a rise in the Earth“s temperature. What Is the Evidence of Warming? Temperature records go back to the late 19th century and show that the global average temperatur

7、e increased by about 0.6 in the 20th century. Sea levels have risen 1020 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 d

8、ecades in summer and autumn. There are 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

9、 done to reduce emissions, current climate models predict a global temperature increase of 1.45.8 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 hun

10、dreds of years to respond to changes 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 indica

11、tions that the west Antarctic ice 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

12、say the risk of drought in inland 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 impac

13、t is huge, with predicted freshwater 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

14、habitats change faster than species 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 Don“t We Know? We don“t know exactly what proportion of the observed warming is caused by hu

15、man activities or what the knock-on 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 warmi

16、ng will cause some changes which will 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

17、 up in warmer conditions, though 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;

18、those who accept the climate 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

19、 of the natural variability 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 Sc

20、ience Program, said trends 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 Earth“s surface. However, scientists involved in the report say better data is badly needed. Observations down

21、the years have suggested that the troposphere, the lower atmosphere, is not warming up, despite evidence that temperatures at the Earth“s 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 rea

22、l warming. The new report, 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 5

23、0 years cannot be explained 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, tropospheri

24、c temperatures have risen by 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. Meteorolo

25、gical Office, who contributed to the report, ascribes this uncertainty to poor data “Basically, we“ve not been observing the atmosphere with climate in mind,“ he told the BBC News website. “We“re looking for very small signals in data that are very noisy. From one day to the next, the temperature ca

26、n change by 10, but we“re looking 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

27、 datasets show more warming at 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 report“s support for the concept of human-induced climate change is spin

28、 rather than substance. “The basic data in the report is quite OK,“ he said, “but the interpretation that“s 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 betw

29、een themselves and the Earth, largely 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 measur

30、ements as they ascend, but scientists 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

31、higher-quality data and resolve 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

32、factors such as wind, clouds, 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 impr

33、ove computer models.（分数：70.00）(1).In the past, the global average temperature may have been 27.（分数：7.00）(2).Water vapor plays almost no role in modern greenhouse warming.（分数：7.00）(3).There are discrepancies between trends in surface temperatures and those in the troposphere in the Antarctic.（分数：7.00

34、4).It may take large bodies of water and ice decades to respond to changes in temperature.（分数：7.00）(5).It is difficult to predict the strong regional variations in the patterns of 1.（分数：7.00）(6).According to the WHO, increases in malaria, water-borne disease and malnutrition could threaten 1.（分数：7

35、00）(7).The release of large quantities of the greenhouse gas methane as permafrost melts will speed up 1.（分数：7.00）(8).A U.S. scientific report concluded that some trends of climate change were caused by 1.（分数：7.00）(9).Most models predict more warming in the troposphere than at the surface, whereas

36、most datasets 1.（分数：7.00）(10).To resolve remaining uncertainties, it“s necessary to observe factors such as wind, clouds, and humidity in the troposphere to make sure they are consistent with 1.（分数：7.00）2.The crop circles were thought to be the greatest works of modem art, the signs of 1 or landing

37、sites of UFOs. （分数：7.00）三、Part Listening Com(总题数：0，分数：0.00)四、Section A(总题数：4，分数：112.00)（分数：21.00）A.20 years ago.B.25 years ago.C.When Shakespeare was there.D.When the restaurant newly opened.A.In the corner near the band.B.In the corner by the window.C.At the table near the bank.D.In a dark room.A.A

38、 green dress.B.A dark red dress.C.A long brown robe.D.A bright golden dress.Directions: In this section, you 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 questions will be

39、 spoken only once. After each question there will be a pause. During the pause, you must read the four choices marked , and decide which is the best answer. Then mark the corresponding letter on Answer Sheet 2 with a single line through the centre. （分数：35.00）A.Call a repairperson soon.B.Ask the man

40、to fix her refrigerator.C.Find a book on how to make repairs.D.Wait to see if the problem disappears.A.She disliked what the man said.B.She agreed with the man“s view.C.She didn“t hear what the man said.D.She didn“t agree with the man“s opinion.A.He definitely doesn“t know the date.B.He is the only

41、person who knows the date.C.He forgot the time when he handed in his assignments.D.The last assignment he handed in was not good.A.He cooks for the club members quite often.B.He wasn“t careful when he was preparing food.C.He often fills the kitchen with tomatoes and chocolate.D.He doesn“t like to pr

42、epare food for the club members.A.Call a taxi for the woman.B.Ride a horse with the woman.C.Go to the bus station himself.D.Drive the woman to the train station.（分数：35.00）A.Public buses are fast and cheap transportation tools.B.Parking is becoming a big problem.C.Subway trains are even safer than ta

43、xies.D.Taxies are more convenient than buses.A.Work out a plan to tighten his budget.B.Find out the opening hours of the cafeteria.C.Apply for a senior position in the restaurant.D.Solve his problem by doing a part-time job.A.The man regrets being absent-minded.B.The woman saved the man some trouble

44、C.The man placed the reading list on a desk.D.The woman emptied the waste paper basket.A.The errors will be corrected soon.B.The woman was mistaken herself.C.The computing system is too complex.D.He has called the woman several times.A.A car dealer.B.A mechanic.C.A driving examiner.D.A technical co

45、nsultant.（分数：21.00）A.One hour.B.Three hours.C.Two hours.D.Four hours.A.She asked for $15.B.She donated $ 50.C.She requested $ 20.D.She gave $10.A.She is poor in English.B.She can“ t speak English.C.She has the ability to act in a play.D.She doesn“ t like to speak English in a play.五、Section B(总题数：3，

46、分数：70.00)（分数：21.00）A.The disadvantages of women compared to men.B.Impacts on marriages caused by financial worries.C.Women are more concerned with money problems.D.Unlike women, men usually have nothing to worry.A.Because many women have to control the expenditure of the whole family.B.Because there

47、s the financial crisis nowadays.C.Because women are usually not good at controlling their personal finances.D.Because women usually earn less than men.A.Women can live 11.5 years longer than men.B.American career women earn 30% less than men on average,C.Women have to work for shorter time than men

48、 though the salaries are equal.D.Women can work 5 to 7 years longer than men.（分数：28.00）A.He was selected for the nationwide competition.B.He ranked as one of the top students in his class.C.He was rewarded a prize.D.He invented his first robot.A.Getting the thousand-dollar prize.B.Developing a new f

49、riendship.C.Helping her with her robot rebuilding.D.Becoming her boy friend.A.Alicia and Nigel were at the same school.B.Alicia didn“t join the robot competition.C.Alicia was helpless when she knew the truth.D.Alicia was aware of Nigel“s intentions.A.Diligent.B.Competitive.C.SelfishD.Sympathetic.（分数：21.00）A.Your folk.B.Polite drivers.C.Traffic jams.D.Pains in head.A.They are not a large group.B.They are so small.C.They follow a simple procedure.D.They are polite to one anoth