大学英语四级新题型模拟训练

　二、长对话
　　Conversation 1
　　19. (A) Two different types of bones in the human body.
　　 (B) How bones help the body move.
　　 (C) How bones continuously repair themselves.
　　 (D) The chemical composition of human bones.
　　20. (A) They defend the bone against viruses.
　　 (B) They prevent oxygen from entering the bone.
　　 (C) They break down bone tissue.
　　 (D) They connect the bone to muscle tissue.
　　21. (A) They have difficulty identifying these cells.
　　 (B) They aren't sure how these cells work.
　　 (C) They've learned how to reproduce these cells.
　　 (D) They've found similar cells in other species.
　　22. (A) To learn how to prevent a bone disease.
　　 (B) To understand differences between bone tissue and other tissue.
　　 (C) To find out how specialized bone cells have evolved.
　　 (D) To create artificial bone tissue.
　　Conversation 2
　　23. (A) A new fuel for buses.
　　 (B) The causes of air pollution.
　　 (C) A way to improve fuel efficiency in buses.
　　 (D) Careers in environmental engineering.
　　24. (A) Her car is being repaired.
　　 (B) She wants to help reduce pollution.
　　 (C) Parking is difficult in the city.
　　 (D) The cost of fuel has increased.
　　25. (A) A fuel that bums cleanly.
　　 (B) An oil additive that helps cool engines.
　　 (C) A material from which filters are made.
　　 (D) An insulating material sprayed on engine parts.
　　三、选词填空
　　 The biggest safety threat facing airlines today may not be a terrorist with a gun, but the man with the 1 computer in business class. In the last 15 years, pilots have reported well over 100 2 that could have been caused by electromagnetic interference. The source of this interference 3 unconfirmed, but increasingly, experts are pointing the blame at portable electronic device such as portable computers, radio and cassette players and mobile telephones.
　　 RTCA, an organization which advises the aviation（航空）industry, has recommended that all airlines ban（禁止）such devices from being used during “ 4 ” stages of flight, 5 take-off and landing. Some experts have gone further, calling for a total ban during all flights. Currently, rules on using these devices are left up to individual airlines. And although some airlines prohibit passengers from using such equipment during take-off and landing, most are 6 to enforce a total ban, given that many passengers want to work during flights.
　　 The difficulty is 7 how electromagnetic fields might affect an aircraft’s computers. Experts know that portable device emit radiation which 8 those wavelengths which aircraft use for navigation and communication. But, because they have not been able to reproduce these effects in a laboratory, they have no way of knowing whether the interference might be dangerous or not.
　　 The fact that aircraft may be vulnerable（易受损的）to interference raises the risk that terrorists may use radio systems in order to damage navigation 9 . As worrying, though, is the passenger who can’t hear the instructions to turn off his radio because the music’s too 10 .
　　A) definite
　　B) incidents
　　C) effects
　　D) remains
　　E) critical
　　F) particularly
　　G) reluctant
　　H) refreshing
　　I) portable
　　J) enormous
　　K) predicting
　　L) liberal
　　M) affects
　　N) equipment
　　O) loud
　四、改错
　　Most people work to earn a living and they
　　produce goods and services. Goods are either
　　agricultural (like maize) or manufactured (like
　　cars). Services are such things like education, 1._________
　　medicine, and commerce. These people provide 2.__________
　　goods; some provide services. Other people provide
　　both goods or services. For example, in the same 3.__________
　　garage a man may buy a car or some service which
　　helps him maintain his car.
　　The work people do is called as economic 4.__________
　　activity. All economic activities taken together make
　　up the economic system of a town, a city, a country,
　　or the world. Such economic system is the sum-total 5.__________
　　of what people do and what they want. The work
　　people do either provides what they need or provides
　　the money with that they can buy essential 6.__________
　　commodities. Of course, most people hope to have
　　enough money to buy commodities and services which
　　are essential but which provide some particular 7. __________
　　personal satisfaction, such as toys for children, visits 8. __________
　　the cinema, and books.
　　The science of economics is basic upon the facts 9. __________
　　of our everyday lives. Economists study our everyday
　　lives and the general life of our communities in order
　　to understand the whole economic system of which we
　　are a part. They try to describe the facts of the
　　economy in which we live, and to explain how it
　　works. The economist methods should of course be 10. __________
　　strictly objective and scientific.