2007年12月英語四級全真預(yù)測試題解析

　　21. What does the professor say about scientists who study the specialized cells in human bones?

　　【解析】[B]女士說這種特殊細胞作用于人類骨頭的過程相當復雜，事實上，連研究人類骨頭的科學家都不能完全了解這個過程。從這一句中可以知道：In fact, the scientists who study human bones don’t completely understand it yet. 所以答案即是這些科學家也不知道這些細胞如何工作。

　　22. According to the student, what is one important purpose of studying specialized cells in human bones?

　　【解析】[A]學習這些人類骨頭中的特殊細胞的重要目的是為了學習如何預(yù)防骨頭疾病。從男士的這一句話中可看出：That’ll prevent the disease from ever occurring. 這樣可以在疾病發(fā)生之前預(yù)防疾病，可見[A]符合題意。

　　Conversation Two

　　M: Hi Diana, mind if I sit down?

　　W: Not at all, Jerry. How have you been?

　　M: Good. But I’m surprised to see you on the city bus. Your car in the shop?

　　W: No. I’ve just been thinking a lot about the environment lately. So I decided the air will be a lot cleaner if we all use public transportation when we could.

　　M: I’m sure you are right. The diesel bus isn’t exactly pollution free.

　　W: True. They’ll be running a lot cleaner soon. We were just talking about that in my environmental engineering class.

　　M: What could the city do? Install pollution filters in all their buses?

　　W: They could, but those filters make the engines work harder and really cut down on the fuel efficiency. Instead they found a way to make their engines more efficient.

　　M: How?

　　W: Well, there is a material that’s a really good insulator. And a thin coat of it gets sprayed on the certain part of the engine.

　　M: An insulator?

　　W:Y eah. What it does is reflect back the heat of burning fuel. So the fuel will burn much hotter and burn up more completely.

　　M: So a lot less unburned fuel comes out to pollute the air.

　　W: And the bus will need less fuel. So with the saving on fuel cost, they say this will all pay for itself in just six months.

　　M: Sounds like people should all go out and get some this stuff to spray their car engines.

　　W: Well, it’s not really that easy. You see, normally, the materials are fine powder. To melt it so you can spray a coat of it on the engine parts, you first have to heat it over 10000 degrees and then, well, you get the idea. It’s not something you or I will be able to do ourselves.

　　Questions 23 to 25 are based on the conversation you have just heard.

　　23. What is the conversation mainly about?

　　【解析】[C]女士說為了環(huán)保應(yīng)該多乘坐公共交通設(shè)備，因此之后的話題便圍繞如何節(jié)能保護環(huán)境的問題展開。這段對話主要討論的是公共汽車的節(jié)能問題，討論了如何讓公共汽車燃料更有效的利用，因此[C]符合題意。

　　24. Why did the woman decide to ride the city bus?

　　【解析】[B]對話開頭部分就交代了此題答案，那位女士說她不開自己的車而該乘公車是為了降低環(huán)境污染。從她提到的So I decided the air will be a lot cleaner if we all use public transportation when we could 即可得知。

　　25. What is the new material?

　　【解析】[D] 這種新的材料是在引擎部位噴灑的一種絕緣材料。從女士的話中there is a material that’s a really good insulator. And a thin coat of it gets sprayed on the certain part of the engine即可得出。這種材料的用途是將燃料燃燒的熱量反射回去，從而達到提高效率的結(jié)果。

　　Section B

　　Passage One

　　A guide dog is a dog especially trained to guide a blind person. Dogs chosen for such training must show good intelligence, physical fitness, and responsibility.

　　At the age of about fourteen months, a guide dog begins an intensive course that lasts from three to five months. It becomes accustomed to the leather harness and stiff leather handle it will wear when guiding its blind owner. The dog learns to watch traffic and to cross streets safely. It also learns to obey any command that might lead its owner into danger.

　　The most important part of the training course is a four�瞱eek program in which the guide dog and its future owner learn to work together. However, many blind people are unsuited by personality to work dogs. Only about a tenth of the blind find a guide dog useful.

　　Questions 26 to 28 are based on the passage you have just heard.

　　26. How long does the intensive course last?

　　【解析】[A]文中明確提到an intensive course that lasts from three to five months，因此正確答案為 [A]。

　　27.Which of the following is not a necessary skill guide dogs have to learn?

　　【解析】[D]答案依據(jù)是The dog learns to watch traffic and to cross streets safely. It also learns to obey any command that might lead its owner into danger. 從這兩句中可看出看家不屬于導盲犬訓練范圍內(nèi)的技能。

　　28.How long does the most important training course last?

　　【解析】[C]最重要的訓練課程持續(xù)四周。文中明確指出了本題答案。The most important part of the training course is a four�瞱eek program，從此句中即可看出。

　　Passage Two

　　People dreams four to six times a night. They dream while they are in the REM stage of sleep, which means rapid eye movement stage in one’s sleep. Sleepers go into the REM stage about every 90 minutes. The first dream of the night may last about ten minutes. Each dream gets a little longer. The last dream of the night may be an hour long.

　　People need their dreams. Younger children spend more time dreaming. Babies spend almost half of their sleep in the REM stage.

　　One experiment showed that everyone needs to dream. Doctors gave some people sleeping pills. These sleeping pills didn’t let them going to REM sleep. After a few nights without dreams, they began to feel bad. They became angry easily, they worried a lot, and they wanted to fight with everyone. Then they stopped taking the sleeping pills. They all began to dream all night for a few nights to catch up.

　　Why do people dream? Dreams give them time to find the answers to some of their problems. If they think they will have difficult problems the next day, they may spend more time on REM sleep the night before. In their dreams, they may find an answer to their problems.

　　Questions 29 to 31 are based on the passage you have just heard.

　　29.How often does a person dream each night?

　　【解析】[B]文章一開始即交待了一個人一晚上要做夢四到六次。從第一句就可看出People dreams four to six times a night.因此，答案為 [B]。

　　30.What is true according to this passage?

　　【解析】[D]安眠藥會阻止人們進入REM睡眠狀態(tài)。These sleeping pills didn’t let them going to REM sleep.可看出 [D] 項正確。

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