大学英语四级模拟题十三及答案Word格式文档下载.docx

1、nd,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 bodyno bigger,perhaps than the earth.Was that why no light could be seen from it?Or were the si

2、gnals 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.In

3、stead,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

4、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 lightif they give much li

5、ghtis 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 C.were heard in 1967 only D.were secret messages 22. The radio singals were sent by_. A.a satelliteB.a plan

6、et 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

7、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 intel

8、ligent 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 f

9、ound 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 earths land is desert or desertlike.About 628 million peopleone out of sevenlive

10、in these dry regions.In the past,they have managed to survive,but with difficulty.ZZ（ZNow largely through problems caused by modern life,their existence is threatened by the slow,steady spread of the earths deserts. Scientists still do not understand all the complex problems of the desert,but there

11、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 w

12、ater.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 collectio

13、n 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 earths 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 t

14、he 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 earths desert are slowly sp

15、reading. 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 Africas desert. Questions 31 to 35 are based on the following passage:Telephone, television, radio, and telegraph all help people com

16、municate with each other. Because of these devices, ideas and news of events spread quickly all over the world. For example, within seconds, people can know the results of an election in another country. An international football match comes into the homes of everyone with a television set.News of a

17、 disaster such as an earthquake or a flood can bring help from distant countries within hours, help is on the way. Because of modern technology like the satellites that travel around the world, information travels fast. How has this speed of communication changed the world? To many people,the world

18、has become smaller. Of course this does not mean that the world is actually physically smaller. It means that the world seems smaller. Two hundred years ago,communication between the continents took a long time. All news was carried on ships that took weeks or even months to cross the ocean. In the

19、seventeenth and eighteenth centuries,it took six weeks for news from Europe to reach America.This time difference influenced peoples actions. For example, one battle, or fight, in the War of 1812 between England and the United States could have been avoided. A peace agreement had already been signed

20、. Peace was made in England, but the news of peace took six weeks to reach America. During these six weeks, the large and serious Battle of New Orleans was fought. Many people lost their lives after a peace treaty had been signed.They would not have died if news had come in time.In the past,communic

21、ation took much time than it does now. There was a good reason why the world seemed so much larger than it does today. 31. News spreads fast because of_. A.modern transportation B.new technology C.the change of the world D.a peace agreement 32. According to this passage,_is very important to people

22、in a disaster area. A.fast communication B.modern technology C.latest news D.new ideas 33. Which of the following statements is true?A.The world now seems smaller because of faster communication. B.The world is actually smaller today. C.The world is changing its size. D. The distance between England

23、 and America has changed since the War of 1812 34. Two hundred years ago,news between the continents was carried_. A.by telephone and telegraph B.by land C.by air D.by sea 35. The New Orleans Battle could have been avoided if the peace agreement had been signed_. A.by both sides B.in time C.in Ameri

24、ca D.in England Questions 36 to 40 are based on the following passage:The concept of personal choice in relation to health behaviors is an important one.An estimated 90 percent of all illnesses may be preventable if individuals would make sound personal health choices based upon current medical know

25、ledge. We all enjoy our freedom of choice and do not like to see it restricted when it is within the legal and moral boundaries of society.ZZ）The structure of American society allows us to make almost all our own personal decisions that may concern our health.If we so desire,we can smoke,drink exces

26、sively, refuse to wear seat belts,eat whatever foods we want,and live a completely sedentary life-style without any excuse.The freedom to make such personal decisions is a fundamental aspect of our society,although the wisdom of these decisions can be questioned.Personal choices relative to health o

27、ften cause a difficulty.As one example,a teenager may know the facts relative to smoking cigarettes and health but may be pressured by friends into believing it is the socially accepted thing to do.A multitude of factors,both inherited and environmental,influence the development of healthrelated beh

28、aviors,and it is beyond the scope of this text to discuss all these factors as they may affect any given individual.However,the decision to adopt a particular health-related behavior is usually one of personal choices. There are healthy choices and there are unhealthy choices.In discussing the moral

29、 of personal choice,Fries and Crapo drew a comparison.ZZ（ZThey suggest that to knowingly give oneself over to a behavior that has a statistical probability of shortening life is similar to attempting suicide.ZZ）Thus,for those individuals who are interested in preserving both the quality and quantity

30、 of life,personal health choices should reflect those behaviors that are associated with statistical probability of increased vitality and longevity. 36. The concept of personal choice concerning health is important because_. A.personal health choices help cure most illnesses B.it helps raise the level of our medical knowledge C.it is essential to