大学四级-915及答案解析.doc

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1、大学四级-915 及答案解析(总分：778.00，做题时间：90 分钟)一、Part Writing(总题数：1，分数：106.00)1.学习英语很重要。2简要介绍你的英语学习经验。3鼓励她学好英语。（分数：106.00）_二、Part Reading Compr(总题数：1，分数：70.00)Rocket RenaissanceThe Ear of Private Spaceflight Is About to StartBackgroundTwo years ago, people witnessed the first space travel by SpaceShip One. Thr

2、ee people were involved in this flight: Burt Rutan, who designed the craft, and Mike Melvill, who flew it-although they were ably assisted by Paul Allen, one of the founders of Microsoft, who paid for it. Certainly, people have long been known that manned spaceflight was possible. What they showed w

3、as that it is not just a game for governments. Private individuals can play, too.People involvedNow, lots of people want to join in, and most of them have just met up at the International Space Development Conference in Los Angeles, to engage in that mixture of camaraderie and competition that chara

4、cterises the beginnings of a new technology. And, as might be expected, they have two of the necessary ingredients of success: ideas and money.First, the money. So far, more than $1 billion is known to have been committed to building private spaceships and the infrastructure to support them. For exa

5、mple, Mr Rum s follow-up vehicle, SpaceShip Two, is expected to cost its backers, Virgin Galactic, $240m for a fleet of five. The spaceport in New Mexico from which these are intended to fly will account for another $225m, although New Mexicos government is planning to raise this money itself.These

6、are not small sums, of course. On the other hand, Virgin Galactic has already banked $14m of deposits towards the $200,000 fare from people who want to travel on SpaceShip Two, even though it has yet to be built, let alone flown.All this suggests that spaceflight, if not exactly entering the age of

7、the common man, is at least entering the age of the moderately prosperous enthusiast. For entrepreneurs, it is no longer necessary to have billions of dollars to get into space; millions will now do. And for those who merely wish to travel there, and have enough money in their bank account, reality

8、is favourable.Get startedAs with aircraft a century ago, a lot of designs are competing with each other, and there is no certainty about which will succeed. The initial goal is to build a “suborbital“ vehicle. This will not have to develop the tremendous speed needed to go into orbit around the Eart

9、h. instead, it will travel briefly into space, offering a short thrilling ride out of the atmosphere, a few minutes of weightlessness, and a spectacular view of the planet from about 100kin. Four important criteria are how you take off, what fuel you use, what your craft is made of, and how you come

10、 back.Most peoples vision of a rocket launch is straight up from the ground. But, of the five vehicles most likely to be developed, two will actually be launched from the air. SpaceShip Two will be carded to high altitude by a purpose-built aircraft known as Eve before its rocket motor is ignited. A

11、nd Explorer, a vehicle being designed by Space Adventures, will be launched from the top of a high-altitude Russian research plane called the M-55X, according to Eric Anderson, the firms president and chief executive.As Dennis Jenkins, a consultant engineer at NASA, Americas space agency, points out

12、, this is similar to using a two-stage rocket to get into space, with the aircraft acting as the first stage. However, a plane offers several advantages over a throw-away booster rocket. First, it can be used again. Second, it uses oxygen from the air, rather than having to carry its own oxidant, wh

13、ich saves weight. Third, it is lifted by wings. That means the atmosphere is an advantage, rather than a hindrance. All this means that the spacecraft itself can be lighter and cheaper.Not everyone wants to run two vehicles, though. Jeff Greason, president of XCOR Aerospace, a firm based in Mojave,

14、California, is developing a two-person, ground-launched suborbital rocketplane called Xerus. Launching from the ground, says Mr. Greason, is more difficult than air launching, but he reckons that in this case it has significantly lower operating costs.Fuel choicesThe second important design choice i

15、s the type of fuel. Unlike a jet engine, a rocket carries its own oxidant (氧第剂). This is why it can operate in space. Sometimes that oxidant is oxygen itself, in liquid form. In that case the fuel, too, is usually liquid-either kerosene (煤油) or liquid hydrogen (氢) and the two liquids are stored in s

16、eparate tanks until they meet in the rockets combustion chamber. Alternatively, both fuel and oxidant are solid, and are loaded pre-mixed, like the propellant of a firework rocket.SpaceShip Two, though, follows the design of SpaceShip One and is powered by a mixture of the two. The combustion chambe

17、r of a mixture is partly filled with solid fuel but no oxidant. However, the fuel is coated round the inside of the chamber, leaving a hole through the middle into which a liquid or gaseous oxidant can be pumped, and out of which the exhaust emerges. In SpaceShip One, the fuel was rubber and the oxi

18、dant a liquefied gas called nitrous oxide (一氧化二氮).Proponents of mixture say they are safer than either pure solid or pure liquid rockets. George Whittinghill, Virgin Galactics chief technologist, says that they are safer than solid rockets because the flow of oxidant can be controlled, and combustio

19、n halted, if there is a problem. Solid rockets, like the fireworks they resemble, cannot be stopped until they run out of fuel. On the other hand liquid-fuelled engines, though they can be shut down, are complex and temperamental. As Mr. Whittinghill observes, “they have pumps, seals, valves and lin

20、es everywhere, and there is a lot that potentially could go wrong.“All this rather irrates those working on liquid propulsion. Richard Pournelle, head of investor relations at XCOR Aerospace, says the comparison is unfair. Liquid propulsion is routine in rocketry while hybrids are still rare. Number

21、s alone, therefore, mean that liquid-fuelled rockets blow up more often. That, Mr. Pournelle argues, does not prove that they are inherently unsafe. Chuck Lauer, vice- president of business development for Rocketplane, another firm going down the liquid-fuelled route, agrees and argues that kerosene

22、 is widely used as aviation fuel and nobody complains that it is unsafe.（分数：70.00）(1).It is only two years ago that people became aware of the fact that manned spaceflight was actually possible.（分数：7.00）填空项 1:_(2).Spaceflight is possible for individuals who want to fly in the space and who have the

23、money.（分数：7.00）填空项 1:_(3).The initial goal of building an aircraft is to make the vehicle fly, and speed was not such a primary consideration.（分数：7.00）填空项 1:_(4).All of the five vehicles most likely to be developed will be launched from the air.（分数：7.00）填空项 1:_(5).Although it is possible to launch t

24、he spaceship both from ground and from the air, some people believe its more cost-effective to launch it from ground.（分数：7.00）填空项 1:_(6).A consultant engineer at NASA points out that using aircraft acting as the first Stage provides several advantages over a throw-away booster rocket.（分数：7.00）填空项 1:

25、_(7).In the design considerations of a spaceship, fuel choice is as important as the method of launching.（分数：7.00）填空项 1:_(8).A rocket carries its own oxidant, and its fuel is usually either kerosene or_.（分数：7.00）填空项 1:_(9).Proponents of mixture say that they are_than either pure solid or pure liquid

26、 rockets.（分数：7.00）填空项 1:_(10).Proponents of kerosene cite the example of_using it as fuel（分数：7.00）填空项 1:_三、Part Listening Com(总题数：0，分数：0.00)四、Section A(总题数：3，分数：105.00)Questions 11 to 18 are based on the conversation you have just heard.（分数：56.00）A.He did not know.B.He thought it was very successful

27、.C.He thought it was bad.D.He thought others perform better.A.It was reported on the radio.B.She read it in the morning news.C.The man called her immediately.D.She was in the neighborhood.A.Playing a piano.B.Making a photocopy.C.Typing.D.Taking a picture.A.He talked with the consultant until two.B.T

28、he consultant was leaving at two.C.The consultant wanted to talk to him, too.D.He couldnt talk to the consultant before two.A.The man doesnt want to take any more courses.B.The bank needs some new employees.C.The woman suggests that the man get a loan from a bank.D.The man does not know how to get f

29、inancial aids.A.Better.B.Tired.C.Bored.D.Sick.A.$160.00.B.$150.00.C.$180.00.D.$120.00.A.He is forgetful.B.His class is easy.C.He is looking for an assistant.D.His course is difficult.Questions 19 to 22 are based on the conversation you have just heard.（分数：28.00）A.Invite the girl to join a party.B.In

30、vite the girl to go shopping.C.Invite the girl to have dinner.D.Invite the girl to watch a movie.A.From his friend.B.From his neighbor.C.From his roommate.D.From a sponsor of the movie.A.For free.B.$50.00 a piece.C.$100.00 a piece.D.He did not tell the girl.A.There will be a lot of people.B.They wil

31、l have dinner together first.C.They live far from the theatre.D.There will be a heavy traffic.Questions 23 to 25 are based on the conversation you have just heard.（分数：21.00）A.Italy.B.England.C.Australia.D.Thailand.A.The cost is low.B.She wants to study English.C.She wants to see kangaroos.D.She want

32、s to enjoy the beautiful natural scenery there.A.Two weeks.B.Three weeks.C.Two months.D.Three months.五、Section B(总题数：3，分数：70.00)Passage OneQuestions 26 to 28 are based on the passage you have just heard.（分数：21.00）A.After the victim is sent to hospital.B.After the causes of the victims suffering beco

33、mes clear.C.After the arrival of the ambulance.D.As soon as possible after the accident or illness.A.Relieve pain.B.Preserve life.C.Keep energy.D.Prevent further harm.A.Immediate action.B.Accurate diagnosis.C.Medical knowledge.D.Expert experience.Passage TwoQuestions 29 to 31 are based on the passag

34、e you have just heard.（分数：21.00）A.How space station works.B.The differences between space and the earth.C.How can people build a space station.D.The reason why people want a space station.A.Scientists are curious about the space.B.Scientists are trying to find a new planet for human beings.C.Scienti

35、sts need to study the influence of gravity on different species.D.Scientists are experimenting with species that can survive only in space.A.Materials science.B.Biotechnology.C.Biomedicine.D.Fluid physics.Passage ThreeQuestions 32 to 35 are based on the passage you have just heard.（分数：28.00）A.Influe

36、nce of mass media on our lives.B.Profitability of mass media.C.Mass media and its short history.D.Mass media and politics.A.1940s.B.1910s.C.1930s.D.1920s.A.Printing.B.Television.C.Record pressing.D.Film duplication.A.People can know everything.B.People can have access to large amount of information.

37、C.People no longer read newspaper.D.People began to rely heavily on computer.六、Section C(总题数：1，分数：143.00)The modem society has witnessed amazing development in astrology. In recent years scientific investigation of comets has (36) because of a growing interest in the origin of the sun and (37) . Sci

38、entists want to learn how comets are formed. They think that such information will be (38) to mans understanding of the origin of the (39) system.The word “comet“ comes from the Greek and means “hairy object“. In history comets have a special place. People believed that they brought news of death, (

39、40) or military victories.The tails of comets provide (41) with spectacular sights at night. Comets tails are millions of kilometers long. The tail (42) reaches lengths of 250 kilometers and more.There was a written (43) of comet as early as 1770 B.C. The Chinese kept careful record and so did the B

40、abylonians. (44) .The most famous comet in history is called Halleys Comet. (45) .It was named after Edmond Halley, an English scientist. (46) The comet appeared in 1758, as he predicted, 16 years after his death and will return again in 1986.（分数：143.00）填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项

41、1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_七、Part Reading Compr(总题数：0，分数：0.00)八、Section A(总题数：1，分数：90.00)There are many theories about the beginning of drama in ancient Greece. The one most widely accepted today is (47) on the assumption that drama (48) from ritual. People might wonder the relationship between

42、these two things. However, the argument for this view goes as follows.In the beginning, human beings viewed the (49) forces of the wordeven seasonal changes as unpredictable, and they sought through various means to control these feared powers. Those (50) which appeared to bring the desired results

43、were then (51) and repeated until they hardened into fixed rituals. Though it is simple to describe the process, they believe, the actual happening might last long. (52) stories arose which explained or veiled the (53) of the rites.As time passed, some rituals were abandoned, but the stories, later

44、called myths, (54) and provided material for art and drama. Those who believe that drama came from ritual also argue that those rites contained the seed of theater (55) music, dance, and masks were almost always used. Furthermore, a suitable site had to be provided for (56) and there was clear divis

45、ion between the “acting area“ and “auditorium“. In addition, there were performers, and, since considerable importance was attached to avoiding mistakes in the enactment of rites, religious leaders usually assumed that task. A) evolvedI) singing B) becauseJ) persisted C) Eventually K) based D) natur

46、al L) measures E) mysteries M) effectiveness F) stopped N) Firstly G) questions O) retained H) performances（分数：90.00）填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_九、Section B(总题数：0，分数：0.00)十、Passage One(总题数：1，分数：44.50)A feature of US education that we have not yet discussed i

47、s continuous classroom interaction between teacher and students. From Los Angeles to New York, and from Chicago to Houston, educators believe that students master information by discovering it for themselves. They believe that teachers do not actually teach, but simply help students learn. In this view, learning takes place through a process of challenging old ideas and asking questions. The faculty member aims to exchange ideas with students, rather than simply tell them what they should know.The concept of constantly exchangi