12月大学英语四级考试模拟试卷及答案(21)

Part Ⅱ Reading Comprehension (35 minutes)

Directions: There are 4 passages in this part.Each passage is followed by some questions or unfinished statements.For each of them there are four choices marked A),B),C) and D).You should decide on the best choice and mark the corresponding letter on the Answer Sheet with a single line through the center.

Questions 21 to 25 are based on the following passage:

Some radio singals were heard in 1967.They were coming from a point in the sky where there was unknown star.They were coming very regularly,too:about once a second,if they were controlled by clock.?

The scientists who heard the signals did not tell anybody else.They were rather afraid to tell in case they frightened people.The signals were coming from a very small body—no bigger,perhaps than the earth.Was that why no light could be seen from it?Or were the signals coming from a planet that belonged to some other star??There was no end to the questions,but the scientists kept the news secret.“Perhaps there are intelligent beings out there.”they thought,“who are trying to send messages to other planets,or to us?So the news was not given to the newspaper.Instead,the scientists studied the signals and searched for others like them...Well,all that happened in 1967 and 1968.Since then scientists have learnt more about those strange,regular,radio signals.And they have told the story,of course.

The signals do not come from a planet;they come from a new kind of star called a “pulsar””.About a hundred other pulsars have now been found,and most of them are very like the first one.?

Pulsars are strong radio stars.They are the smallest but the heaviest stars we know at present.A handful of pulsar would weigh a few thousand tons.Their light—if they give much light—is too small for us to see.But we can be sure of this,no intelligent beings are living on them.

21. The radio signals discussed in this passage____.?

A.were regular B.were controlled by a clock?
答案

1

短文大意

1967年人类收到了一些太空信号。这些信号来自太空中的某一恒星领域,它们极有规律,难道这是外星人向地球或我们发收的信号?为了不致在人们当中造成恐慌,科学家们一直保守着这个秘密,并且一直对它们进行研究。如今,当然一切都真相大白。原来这些信号都来自一种叫脉冲星的恒星,它们的密度极大连光线也难以逃逸。但有一点可以确定,上面没有智能生命存在。

21. 答案A。?

【参考译文】 文中讨论到的电磁信号……?

【试题分析】 此题考查考生“辨认事实”的能力。?

【详细解答】 见原文第一段,“They were coming very regularly,too.”他们同样非常有规律,与 A)项同意。B)were controlled by a clock.由时钟控制,原文前面有一表示“似乎的”连词 if。C),D)根据下文判断都不正确。 ?

22. 答案C。?

【参考译文】 这些电磁信号来自于……?

【试题分析】 此题考查考生“根据已知信息进行推断”的能力。?

【详细解答】 见原文第三段“...they come from a new kind of star called a “pulsar””他们来自一种叫脉冲星的新型恒星。 A) a satellite卫星,B)a planet行星,D)当时未知的智能生命。 ?

23. 答案C。?

【参考译文】 科学家们没有把有关电磁信号的事情告诉人们是因为……?

【试题分析】 此题考查考生“理解文章中某些细节”的能力。

?【详细解答】 见原文第二段开头“ The scientists who heard the singals did not tell anybody else.They were rather afraid to tell in case they frightened people.”听到该信号的科学家未告诉别人,他们害怕这样会惊吓了老百姓。因此选择 C。 ?

24. 答案A。?

【参考译文】 脉冲星是……?

【试题分析】 此题考查考生“辨认事实”的能力。?

【详细解答】 见原文第四段,实际由“star”这个单词就可排除B),C)和D)选项。

25. 答案D。?

【参考译文】 以下说法,哪一个是正确的??

【试题分析】 此题考查考生“根据已知信息进行推理”的能力。?

【详细解答】 见原文第三段最后一句“About a hundred other pulsars have now been found...”因此D)项正确,其他各项均与原文意思不符。 ?

2

短文大意

本文主要讨论的是沙漠扩张的问题。人们赖以生存的降雨及植被在不断减少,地球上 40%的土地已成了沙漠或已沙漠化, 1/7的人口生活在干旱地区,以及现代生活造成的一些问题使人类生存日益受到沙漠扩张的威胁。虽然科学家还未能彻底了解沙漠问题,但是一些保护土地的措施已被采用,人们在与沙漠抗争。

26. 答案A。?

【参考译文】 本文主要谈论的是什么??

【试题分析】 此题考查考生“把握文章主旨及大意”的能力。

【详细解答】 全文主要阐述了沙漠扩散带来的水源缺乏的问题,以及人们采取的措施。 A)符合该中心思想;B),C)和D)虽在文中提到过但作为主要思想,过于片面。 ?

27. 答案C。?

【参考译文】 1/7指的是……?

【试题分析】 此题考查考生“理解文章中某些细节”的能力。

【详细解答】 见原文第一段第三句“ About 628 million people -one out of seven-live in these dry regions.”大约628,000,000(约为1/7)的人住在这些干旱地区。C)项符合所指代的内容,为正确答案。 ?

28. 答案C。?

【参考译文】 在第二段中,“他们被送往南方的绿草地”,他们指的是……?

【试题分析】 此题考查考生“理解文章中某些细节”的能力。

【详细解答】 见原文最后一句“ Some Sahel farmers still raise cattle on their poor farm land,but before the cattle are sold,they are taken to greener lands in the south to get fat”一些Sahel农民在他们贫瘠的农场上仍然饲养着牛群,但在把他们卖出之前,往往要送到南方多草的土地上以增肥。 they指代前面的the cattle。因此C为正确选项。 ?

29. 答案D。?

【参考译文】 文中描述了几种保护土地的创意??

【试题分析】 此题考查考生“根据已知信息进行推断”的能力。?

【详细解答】 见原文第二段“...but there have been many ideas for saving the land.”但已有了许多保护土地的创意。以下各句即为例证,确定其数目为 3,因此D为正确选项。

30. 答案A。?

【参考译文】 根据短文,以下说法,哪个是正确的??

【试题分析】 此题考查考生“辨认事实”的能力。?

【详细解答】 见原文第一段最后一句“Now largely through problems caused by modern life,their existence is threatened by the slow,steady spread of the earth's deserts.”现在由于现代生活产生的一些问题,他们生存日益受到地球沙漠逐步缓慢扩散的威胁。因此A为正确选择。B)中正确数目应为one out of seven,C)应是modern problems,D)文中未提及。 ?

C.were heard in 1967 only D.were secret messages ?

22. The radio singals were sent by____.?

A.a satellite?B.a planet?

C.a sky body which was unknown at that time?

D.intelligent beings who were unknown at that time ?

23. The scientists did not tell people about the signals because____.?

A.the singals stood for secret messages?

B.people would ask them too many questions?

C.they did not want to frighten people?

D.they stood for unimportant messages ?

24. A pulsar is____.?

A. a small heavy star which sends out strong radio signals and cannot be seen ?

B. a small heavy planet which sends out strong radio signals and cannot be seen ?

C. a small heavy satellite which sends out strong radio signals and cannot be seen

D. a small intelligent being who sends out strong radio signals and cannot be seen

25. Which of the following is true??

A.One of the pulsars found by scientists sends radio signals.?

B.Pulsar began to send radio singals in 1967.?

C.Scientists have searched for pulsars for many years but found none.?

D.Scientists have found many pulsars since 1967. ?

Questions 26 to 30 are based on the following passage:?

Over vast areas of every continent,the rainfall and vegetation necessary for life are disappearing.Already more than 40 percent of the earth's land is desert or desert?like.About 628 million people—one out of seven—live in these dry regions.In the past,they have managed to survive,but with difficulty.[ZZ(Z]Now largely through problems caused by modern life,their existence is threatened by the slow,steady spread of the earth's deserts.

Scientists still do not understand all the complex problems of the desert,but there have been many ideas for saving the land.Sandi Arabia has planted 10 million trees to help keep the sand from taking over fertile areas.The Israelis are aga in using some of the water collection systems left by the ancient people in the

Negev desert.They plan to water their orchards with the extra water.Some Sahel farmers still raise cattle on their poor farm land,but before the cattle are sold, they are taken to greener lands in the south to get fat.

26. What is the article mainly concerned??

A.The problem of spreading desert.?

B.The rainfall and vegetation in desert areas.?

C.The water collection systems.?

D.The difference between modern life and ancient life. ?

27. “one out of seven” refers to____.?

A.more than a third of the lands' earth?

B.the percentage of the earth's land that is desert-like?

C.the number of people who live in dry regions?

D.a day of a week ?

28. In paragraph 2,“they are taken to the greener lands in the south.”They

refers to____.?

A.the Sahel farm land B.the farmers?

C.the cattles D.the trees ?

29. How many ideas for saving the land are described??

A.Five. B.Two.?

C.Four. D.Three. ?

30. Which of the following statements is true, according to the passage??

A.The earth's desert are slowly spreading.?

B.One out of 10 people lives in dry regions.?

C.Their life in the desert is threatened now by traditional problems.?

D.New water wells can solve the problem in Africa's desert. ?