3.第四部分：阅读理解 第一篇
Sunbath and Skin Cancer
In the summer, millions of Americans will offer up their bodies to the sun rays. A tan indicates health and beauty, and most sun worshippers will sacrifice a lot to achieve it , including themselves.
With each hour, the sun's ultraviolet radiation produces irreversible damage, hastening the development of unsightly wrinkles. And with each year on the beach or rooftop, the sunbather¹ increases his risk of getting skin cancer. Skin cancer is by far the most common form of cancer. An estimated 400,000 new cases will be detected this year in the United States, and almost all of them can be blamed on over-exposure to the sun.
Fortunately, most of these cancers are highly curable. But they can be disfiguring and take time to treat. For that reason, sun worshippers should treat deity² with a good deal of awe³. Sunburn, of course, is the initial hazard posed by UV radiation. Prolonged exposure to UV, however, interferes⁴ with the production of collagen fibers⁵ in the dermis⁶, causing the skin to lose elasticity⁷ and creating premature⁸ wrinkles. Further deterioration⁹ of the dermis deprives the epidermis¹⁰ of nutrition and causes it to become thin and dry.
Cancer is UV's final result. Shortwave radiant energy, especially from the UV-B band, breaks the strands¹¹ of DNA¹². Enzymes¹³ work constantly to rearrange the DNA into proper sequence, but with repeated UV exposure, the repair process may eventually break down. Then the mutant DNA may produce a colony of cancer cells. But skin cancer may be avoided with a good dose of common sense. People with fair skin and blue eyes who burn easily stand the highest risk. Special danger spots are the parts of the body most constantly exposed to the sun, such as the cheeks, nose, lower lip and the ears. People who have already developed precancerous lesions or had one skin-cancer growth stand a greatly increased chance of developing others.
Dermatologists¹⁴ recommend avoiding the sun when it is most intense between 11 a.m. and 3 p.m. Anyone who insists on sunbathing¹⁵ should use a good sun screen. These lotions¹⁶ and salves contain chemicals that block out the burning UVB radiation while permitting the tanning rays to reach the skin.
31. According to the passage, over-exposure to the sun may result in ______
A. the wrinkles that cannot be seen.
B. the skin cancer.
C. all kinds of sacrifices.
D. healthful beauty.
32. The underlined word “deity” in the third paragraph refers to ________
A. something mysterious.
B. the skin cancer.
C. the sun.
D. overexposure to the sun.
33. Which of the following comes first as a possible damage by UV radiation?
A. Sunburn.
B. The loss of skin elasticity.
C. Dryness of epidermis.
D. The deterioration of dermis.
34. Why may the repair process of the DNA finally fail?
A. Because shortwave radiant energy breaks the strands of the DNA.
B. Because the DNA may produce a colony of cancer cells.
C. Because enzymes work to rearrange the DNA into a new order.
D. Because the patient is exposed to UV from time to time.
35. The last paragraph of the passage mainly discusses________
A. the treatment of the skin cancer.
B. the prevention of the skin cancer.
C. the parts of the body where cancer is most likely to develop.
D. the lotions that work best in fighting against the skin cancer.
4.第四部分：阅读理解 第二篇
Population Densities¹⁷
The average population density¹⁸ of the world is 47 persons per square mile. Continental¹⁹ densities range from no permanent inhabitants in Antarctica to 211 per square mile in Europe. In the western hemisphere, population densities range from about 4 per square mile in Canada to 675 per square mile in Puerto Rico. In Europe the range is from 4 per square mile in Iceland to 831 per square mile in the Netherlands.
Within countries there are wide variations of population densities. For example, in Egypt, the average is 55 persons per square mile, but 1,300 person inhabit each square mile in settled portions where the land is arable²⁰.
High population densities generally occur in regions of developed industrialization, such as the Netherlands, Belgium, and Great Britain, or where lands are intensively used for agriculture, as in Puerto Rico and Java. Low average population densities are characteristic of most underdeveloped countries.
Low density of population is generally associated with a relatively²¹ low percentage of cultivated land. This generally results from poor quality lands. It may also be due to natural obstacles to cultivation²², such as deserts, mountains, or malaria-infested jungles; to land uses other than cultivation, as pasture and forested land; to primitive²³ methods that limit cultivation; to social obstacles.
More economically advanced countries of low population density have, as a rule, large proportions of their populations living in urban areas. Their rural population densities are usually very low. Poorly developed countries of correspondingly low population density, on the other hand, often have a concentration of rural population living on arable land, which is as great as the rural concentration found in the most densely²⁴ populated industrial countries.
36. Along the banks of the Nile, we may expect to find _______.
A. 1300 persons per square mile
B. few inhabitants
C. no inhabitant
D. few settlements
37. The most densely populated continent is ________.
A. Asia
B. Africa
C. Europe
D. North America
38. There are no permanent inhabitants in Antarctica because ________.
A. it is too hot
B. it is too cold
C. there is no transportation
D. it has only recently been discovered
39. Puerto Rico is a land of ________.
A. heavy industrialization
B. poverty
C. intense agriculture
D. large cities
40. Advanced countries of low population density may well have ________.
A. epidemics
B. arable land
C. large rural population
D. large urban population
5.第四部分：阅读理解 第三篇
Early or Later Day Care
The British psychoanalyst John Bowlby maintains that separation from the parents during the sensitive “attachment” period from birth to three may scar a child's personality and predispose to emotional problems in later life. Some people have drawn²⁵ the conclusion from Bowlby's work that children should not be subjected to day care before the age of three because of the parental²⁶ separation it entails²⁷, and many people do believe this. But there are also arguments against such a strong conclusion.
Firstly, anthropologists point out that the insulated love affair between children and parents found in modern societies does not usually exist in traditional societies. For example, in some tribal²⁸ societies, such as the Ngonim, the father and mother of a child did not rear their infant alone - far from it. Secondly²⁹, common sense tells us that day care would not be so widespread today if parents, care-takers found children had problems with it. Statistical³⁰ studies of this kind have not yet been carried out, and even if they were, the results would be certain to be complicated and controversial. Thirdly, in the last decade there have been a number of careful American studies of children in day care, and they have uniformly reported that day care had a neutral or slightly positive effect on children's development. But tests that have had to be used to measure this development are not widely enough accepted to settle the issue.
But Bowlby's analysis raises the possibility that early day care has delayed effects. The possibility that such care might lead to, say, more mental illness or crime 15 or 20 years later can only be explored by the use of statistics. Whatever the long-term effects, parents sometimes find the immediate³¹ effects difficult to deal with. Children under three are likely to protest at leaving their parents and show unhappiness. At the age of three or three and a half almost all children find the transition to nursery easy, and this is undoubtedly³² why more and more parents make use of child care at this time. The matter, then is far from clear-cut, though experience and available evidence indicate that early care is reasonable for infants.
41. Which of the following statements would Bowlby support?
A. Statistical studies should be carried out to assess the positive effect of day care for children at the age of three or older.
B. Early day care can delay the occurrence of mental illness in children.
C. The first three years of one's life is extremely important to the later development of personality.
D. Children under three get used to the life at nursery schools more readily than children over three.
42. Which of the following is derivable³³ from Bowlby's work?
A. Mothers should not send their children to day care centers before the age of three.
B. Day care nurseries have positive effects on a child's development.
C. A child sent to a day care center before the age of three may have emotional problems in later life.
D. Day care would not be so popular if it has noticeable negative effects on a child's personality.
43. It is suggested that modern societies differ from traditional societies in that _______.
A. the parents-child relationship is more exclusive in modern societies
B. A child more often grows up with his/her brothers or sisters in traditional societies
C. Mother brings up children with the help of her husband in traditional societies
D. Children in modern societies are more likely to develop mental illness in later years
44. Which of the following statements is NOT an argument against Bowlby's theory?
A. Many studies show that day care has a positive effect on children's development.
B. The fact that there are so many nursery schools today shows that day care is safe.
C. The separation of young children from their parents is common in some traditional societies.
D. Parents find the immediate effects of early day care difficult to deal with.
45. Which of the following best expresses the writer's attitude towards early day care?
A. children under three should stay with their parents.
B. Early day care has positive effects on children's development.
C. The issue is controversial and its settlement calls for the use of statistics.
D. The effects of early day care on children are exaggerated and parents should ignore the issue.

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