大学英语四级试题Word文档下载推荐.docx

1、For this part，you are allowed 30 minutes to write a composition on the topic Should Smoking Be Completely Banned. You should write at least 120 words following the outline given below in Chinese:1. 有人赞同完全禁止吸烟，理由是2. 有人不赞同完全禁止吸烟，理由是3. 我看法。Should Smoking Be Completely BannedPart IIReading Comprehension

2、 （Skimming and Scanning）（15 minutes）Directions：In this part，you will have 15 minutes to go over the passage quickly and answer the questions on Answer Sheet 1.For questions 1-7，markY （for YES） if the statement agrees with the information given in the passage;N （for NO）if the statement contradicts th

3、e information given in the passage;NG （for NOT GIVEN） if the information is not given in the passage.For questions 8-10，complete the sentences with the information given in the passage.SpaceOur Future in Space：It Has Already Begun!We are all space travelers. But weve stayed close to home until now.

4、One day，we may leave our “mother ship” Earth to make our home among the stars.A giant，spherical “spaceship”，about 8,000 miles in diameter，is speeding through the solar system right now. It is cruising at an incredible 66,600 miles per hour.Its not a giant，Star Wars mother-ship. Its spaceship Earth，t

5、he home of over four billion people. This water coated spaceship has been traveling through the universe for about five billion years. Only within the past 25 years，however，have some of its passengers broken free of Earths gravity.But 25 years from now，many people，including you，might live in an orbi

6、ting space station 200 miles above the Earth.Space CitiesScientists have already designed special space factories. These factories will take advantage of the absence of gravity （zero gravity） to produce everything from life-saving drugs to perfect ball bearings.Other scientists have designed space c

7、olonies，complete with farms，schools，and artificial day and night. Hundreds，or even thousands，of people will live，work，playeven go to school，far above the Earth.Our conquest of space，of course，has already begun. We have explored part of the Moon，sent robot spaceships onto the surface of Venus and Mar

8、s，and aimed space probes past the planets of Jupiter and Saturn.Last June，one robot ship，Pioneer 10，left our solar system forever. And astronauts from both the Soviet Union and the United States have lived in space stations.The conquest of space，without question，is one of the greatest adventures hum

9、an beings have ever set out on. But it may be more than a great adventure. Some scientists think the conquest of space may be a necessity for survival of the human species.We are tearing up more and more of the Earth to get raw materials for industry. And we are polluting the air and water as we man

10、ufacture products that we need or want. Almost everything that seems to make our lives more comfortable，and from electricity to pesticides，uses up or alters a piece of our planets natural environment.Why Go into Space?Yet our solar system is full of resources. The moon is chockfull of valuable metal

11、s. So are the asteroids，the small，rocky，planet-like bodies orbiting the sun most of them between Mars and Jupiter. These metals，if we can get them，could be used to build factories and space stations.Also，in space，there is no atmosphere to filter out the suns energy. There is plenty of solar energy t

12、o be turned into electricity for manufacturing，for creating comfortable living conditions.Getting away from Earth has other advantages，too. Modern industry uses many kinds of metal alloys （mixtures of metal that are better for certain purposes than pure metals）. Yet some metal alloys either cant be

13、made or are very expensive to make on Earth because of gravity. For instance，certain metals dont mix well on Earth. But in zero gravity，molten （hot，liquid） metals mix more evenly. This is because there is no gravity to pull the heavier metals down，while the lighter ones float on top.From space，too，w

14、e can look down on the Earth and study the atmosphere，its weather，and the effects of air pollution.And because there is no strong gravity to break free from，our future homes away from Earth will be convenient starting points for travel to distant planets.But，while going into space might solve some p

15、roblems，outer space can also be a dangerous place. For example，in outer space，we have to protect ourselves from the dangers of ultraviolet light and cosmic rays. Ultraviolet light from the sun can give us bad sunburns right here on Earth. Yet，Earths atmosphere screens out most of that harmful radiation. Cosmic rays are tiny high energy particles from outer space. Again，the Earth shields us from most of them.At Home in Space?But in space，without special protection，we would be exposed to much stronger radiation from ultraviolet light and cosmic rays. Also，in the zero gravity of outer s