[外语类试卷]大学英语四级模拟试卷803及答案与解析.doc

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1、大学英语四级模拟试卷 803及答案与解析 一、 Part I Writing (30 minutes) 1 For this part, you are allowed 30 minutes to write a composition on the topic: Should Private Cars Be Encouraged in China? You should write at least 120 words following the outline given below in Chinese. 1. 在中国，私人汽车拥有量在增加 2有些人赞成拥有私人汽车，有些人反对拥有私人汽

2、车 3你的观点 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 1-7, mark： Y (for YES) if the statement agrees with the information given in

3、 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 THE HYDROGEN ECONOMY It seems-like every day there is a new announcement in the news about automobiles powered by fuel cells. The promises

4、are great, since fuel cells have the potential to very quickly double the efficiency of cars while significantly reducing air pollution. At the same time, there have been news stories for decades about the problems associated With petroleum. Everything from oil spills to ozone(臭氧 ) alerts to global

5、warming gets blamed on our dependence on fossil(化石 ) fuels. These two forces are leading the world toward what is broadly known as the hydrogen economy. If the predictions are true, over the next several decades we will all begin to see an amazing shift away from the fossil fuel economy we have toda

6、y toward a much cleaner hydrogen future. Problems with the fossil fuel economy While fossil fuels have played an important role in getting society to the point it is at today, there are four big problems that fossil fuels create: Air pollution-When cars burn gasoline, the internal combustion engine

7、also produces: Carbon monoxide, a poisonous gas Nitrogen oxides, the main source of urban smog Unburned hydrocarbons, the main source of urban ozone Environmental pollution-The process of transporting and storing oil has a big impact on the environment whenever something goes wrong. An oil spill, pi

8、peline explosion or well fire can create a huge mess. Global warming The carbon dioxide coming out of every cars tailpipe is a greenhouse gas that is slowly raising the temperature of the planet. The ultimate effects are unknown, but it is a strong possibility that, eventually, there will be dramati

9、c climate changes that affect everyone on the planet. Dependence-The United States, and most other Countries, cannot produce enough oil to meet demand, so they import it from oil-rich countries. That creates an economic dependence. When Middle East oil producers decide to raise the price of oil, the

10、 rest of the world has little choice but to pay the higher price. Advantages of the hydrogen economy The hydrogen economy promises to eliminate all of the problems that the fossil fuel economy creates. Therefore, the advantages of the hydrogen economy include: The elimination of pollution caused by

11、fossil fuels-When hydrogen is used in a fuel cell to create power, it is a completely clean technology. The only byproduct is water. There are also no environmental dangers like oil spills to worry about with hydrogen. The elimination of greenhouse gases-If the hydrogen comes from the electrolysis o

12、f water, then hydrogen adds no greenhouse gases to the environment. There is a perfect cycle-electrolysis produces hydrogen from water, and the hydrogen recombines with oxygen to create water and power in a fuel cell. The elimination of economic dependence-The elimination of oil means no dependence

13、on the Middle East and its oil reserves. Distributed production-Hydrogen can be produced anywhere that you have electricity and water. People can even produce it in their homes with relatively simple technology. The problems with the fossil fuel economy are so great, and the environmental advantages

14、 of the hydrogen economy so significant, that the push toward the hydrogen economy is very strong. Technological Hurdles(障碍 ) The big question with the hydrogen economy is, “Where does the hydrogen come from?“ After that comes the question of transporting, distributing and storing hydrogen. Hydrogen

15、 tends to be large and tricky in its natural gaseous form. Once both of these questions are answered in an economical way, the hydrogen economy will be in place. Where does the hydrogen come from? There are two possible sources for the hydrogen: Electrolysis of water-Using electricity, it is easy to

16、 split water molecules to create pure hydrogen and oxygen. One big advantage of this process is that you can do it anywhere. For example, you could have a box in your garage producing hydrogen from tap water, and you could fuel your car with that hydrogen. Reforming fossil fuels-Oil and natural, gas

17、 contain hydrocarbons-molecules consisting of hydrogen and carbon. Using a device called a fuel processor or a reformer, you can split the hydrogen off the carbon in a hydrocarbon relatively easily and then use the hydrogen. You discard the leftover carbon to the atmosphere as carbon dioxide. The se

18、cond option is, of course, slightly perverse(不正当的 ). You are using fossil fuel as the source of hydrogen for the hydrogen economy. This approach reduces air pollution, but it doesnt solve either the greenhouse gas problem or the dependence problem. However, it may be a good temporary step to take du

19、ring the transition(转变 ) to the hydrogen economy. The interesting thing about the first option is that it is the core of the real hydrogen economy. To have a pure hydrogen economy, the hydrogen must be derived from renewable sources rather than fossil fuels so that we stop releasing carbon into the

20、atmosphere. Having enough electricity to separate hydrogen from water, and generating that electricity without using fossil fuels, will be the biggest change that we see in creating the hydrogen economy. Where will the electricity for the electrolysis of water come from? Currently, about 68 percent

21、of the electricity produced in the United States comes from coal or natural gas. All of that generating capacity will have to he replaced by renewable sources in the hydrogen economy. Right now there are several different ways to create electricity that do not use fossil fuels: Nuclear power Hydroel

22、ectric dams Solar cells Wind turbines Geothermal power Wave and tidal power Co-generation How do you store and transport the hydrogen? Hydrogen is a large gas of its kind, and it is not nearly as easy to work with as gasoline. Compressing the gas requires energy, and compressed hydrogen contains far

23、 less energy than the same volume of gasoline. However, solutions to the hydrogen storage problem are surfacing. For example, hydrogen can be stored in a solid form in a chemical called sodium borohydride. Once the storage problem is solved and standardized, then a network of hydrogen stations and t

24、he transportation infrastructure will have to develop around it. The main barrier to this might be the technological sorting-out process. Stations will not develop quickly until there is a storage technology that clearly dominates the marketplace. For instance, if all hydrogen-powered cars from all

25、manufacturers used sodium borohydride, then a station network could develop quickly; that sort of standardization is unlikely to happen rapidly, if history is any guide. Prospects for the future You will hear more and more about the hydrogen economy in the news in the Coming months, because the drum

26、beat is growing louder. The environmental problems of the fossil fuel economy are combining with breakthroughs(突破 ) in fuel-cell technology, and the pairing will allow us to take the first steps, The most obvious step we will see is the marketing of fuel-cell-powered vehicles. Although they will be

27、powered initially by gasoline and reformers, fuel cells represent two major improvements over the internal combustion engine: They are about twice as efficient. They can significantly reduce air pollution in cities. 2 The passage gives a general description of the benefits and potential problems of

28、a hydrogen economy. （ A） Y （ B） N （ C） NG 3 An oil spill can pose a big problem to the environment. （ A） Y （ B） N （ C） NG 4 Compared with other major industrialized countries, the United States depends more heavily on oil import. （ A） Y （ B） N （ C） NG 5 Even if you have electricity and water, you st

29、ill cannot produce hydrogen everywhere. （ A） Y （ B） N （ C） NG 6 In the United States, most of the electricity is generated from coal or natural gas. （ A） Y （ B） N （ C） NG 7 We must derive hydrogen from renewable sources with a view to a pure hydrogen economy. （ A） Y （ B） N （ C） NG 8 So far, there se

30、ems to be no solution in sight as to how the hydrogen can be stored. （ A） Y （ B） N （ C） NG 9 Possible sources for the hydrogen are both electrolysis of water and _. 10 If the storage problem is _ and _, a network of hydrogen stations and the transportation infrastructure will have to develop around

31、it. 11 Concerning the future of the hydrogen economy, the most obvious step we will take is _. Section A 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 conve

32、rsation 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） The movie was already over, （ B） Some people were watching the movie. （ C） The man had bette

33、r not come over to watch the movie. （ D） The man could come over to watch the movie with some people. （ A） Mr. John is very kind. （ B） The man should notworry. （ C） She worries about him. （ D） She likes to talk with Mr. John. （ A） Nick cant go on studying because he, has to work in a plant. （ B） Nic

34、k has earned enough money for his senior year. （ C） Nick prefers working in a steel plant to studying in a college. （ D） Nick doesnt have enough money so hell work during his senior year. （ A） Steve becomes a millionaire. （ B） Steve owns a luxurious ear. （ C） Steve pretends to be a millionaire. （ D）

35、 People believe Steve is a millionaire. （ A） He is ready to help Prof. Smith. （ B） He will congratulate Prof. Smith. （ C） He will pay a visit to Prof. Smith. （ D） He will tell Prof. Smith the goad news. （ A） Its larger. （ B） Its larger inside. （ C） Its nicer-looking. （ D） Its nicer-looking inside. （

36、 A） She went to the party without knowing it. （ B） She was invited to the party. （ C） She was present for the party. （ D） She was absent from the party. （ A） The womans job as a librarian. （ B） Womens rights in society. （ C） Womens right to vote. （ D） Career planning. （ A） Family name first, given n

37、ame last. （ B） Given name first, family name last. （ C） Middle name first, family name last. （ D） Given name first, middle name last. （ A） Mr. （ B） Mrs. （ C） Ms. （ D） Professor. （ A） Use the formal manner of address. （ B） Use the informal manner of address. （ C） Address people by their first names.

38、（ D） Address people by their last names. （ A） Both a final examination and a term paper. （ B） Only a final examination. （ C） Only a term paper. （ D） Either a final examination or a term paper. Section B Directions: In this section, you will hear 3 short passages. At the end of each passage, you will

39、 hear some questions. Both the passage and 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） Because of their strong desire for good health. （ B） Because of their love for hobbies and pastimes. （ C） Bec

40、ause of their fear of heart disease. （ D） Because of their extra energy. （ A） Because the time of a period is too long. （ B） Because they are lack of sleep. （ C） Because they are not interested in the class. （ D） Because they want to go out and play. （ A） It will make them ill. （ B） It wont influenc

41、e them much. （ C） It will have huge influence on their well-being. （ D） It will seldom bring disasters to them. （ A） Start class earlier. （ B） Emphasize the first and second period classes. （ C） Delay the first period for 30 minutes. （ D） Change the content of the courses. （ A） They can do better th

42、an others. （ B） It is expensive to hire labour. （ C） They dont like to be helped. （ D） They dont trust others. （ A） It publishes books only for children. （ B） It publishes books about peoples pets. （ C） It uses computers to make up stories. （ D） It makes the young readers the leading characters in t

43、he stories. （ A） Written by children themselves. （ B） Telling stories about the reader himself. （ C） Printed with standard things. （ D） Published with the help of computers. Section C Directions: In this section, you will hear a passage three times. When the passage is read for the first time, you s

44、hould 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 are required to fill in the missing information. For these blanks,

45、you can either use the exact words you have just heard or write down the 30 Suppose we built a robot(机器人 )to explore the planet Mars. We provide the robot with seeing detectors to keep it away from【 B1】 _. It is powered entirely by the sun. Should we program the robot to be【 B2】 _active at all times

46、? No. The robot would be using up【 B3】 _at a time when it was not【 B4】 _any. So we would probably program it to【 B5】 _its activity at night and to wake up at dawn the next morning. According to the evolutionary(进化的 )theory of sleep, evolution equipped us with a regular【 B6】 _of sleeping and waking f

47、or the same reason. The theory does not deny(否认 )that sleep【 B7】 _some important restorative functions. It merely says that evolution has programmed us to perform those functions at a time when activity would be【 B8】 _and possibly dangerous. However, sleep protects us only from the sort of trouble w

48、e might walk into;【 B9】 _So we sleep well when we are in familiar, safe place, but we sleep lightly, if at all, when we fear that bears will nose into the tent. The evolutionary theory accounts well for differences in sleep among creatures.【 B10】 _Surely cats do not need five times as much repair an

49、d restoration as horses do. But cats can afford to have long periods of inactivity because they spend little time eating and are unlikely to be attacked while they sleep. Horses must spend almost all their waking hours eating, because what they eat is very low in energy value.【 B11】_. 31 【 B1】 32 【 B2】 33 【 B3】 34 【 B4】 35 【 B5】 36 【 B6】 37 【 B7】 38 【 B8】 39 【 B9】 40 【 B10】 41 【 B11】 Section A Directions: In this section, the