题目内容
阅读理解
In the middle of winter, when snow is falling in many parts of the United States. Scientists have sounded the sun this summer. The warning: The sun’s summer time rays are more dangerous than once thought.
A team of scientists from 80 nations recently reported to the United Nations that a layer of ozone(臭氧层) in the atmosphere, which protects humans from harmful levels of ultraviolet (紫外的) radiation, will be thinner over the United States this summer. The thinner layer allows more ultraviolet rays from the sun to reach earth. The extra amount of ultraviolet radiation could cause an increase in the number of cases of skin cancer.
Scientists first became concerned about the ozone layer in the mid-1980s when a hole was discovered in the layer above Antarctic during the winter. The hole was caused by chemicals used in refrigerators and air conditioners. When these chemicals are sent out into the atmosphere, they produce gases that destroy the ozone.
Concern about the protective ozone layer rose more recently when data (数据) from satellites and ground stations showed that ozone levels were dropping over areas other than Antarctic. Low ozone Levels were recorded in the spring and summer over the United States and over other populated areas in the world.
Although many countries have already begun stopping the use of ozone-destroying chemicals, the new findings are? expected to advance the timetable for a total ban(禁止) of the chemicals.
1．The scientists have observed the ozone layer ________.
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2．The ozone layer in the atmosphere can ________.
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A．do a lot of good to human beings in many ways
B．protect humans from diseases caused by bad weather
C．do a lot of harm to human beings in the summer time
D．protect humans from harmful levels of ultraviolet radiation
3．Scientists first found that there was a hole in the ozone layer ________.
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A．above Arctic during the winter in the mid-1980
B．above Antarctic during the winter in the mid-1980
C．over somewhere in the north of the equator in 1980
D．over somewhere in the summer time in the mid-1980s
4．The damage to the ozone layer was caused by ________.
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A．the changeable weather
B．ozone-destroying chemicals
C．chemicals from refrigerators
D．chemicals from air conditioners
5．Which of the following is NOT true?
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A．The use of ozone-destroying chemicals have already been stopped.
B．The ozone levels in the spring and summer over the USA were low.
C．More and more people have begun to protect the natural surroundings.
D．Many countries have already taken measures to protect ozone layer.
解析：
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1．文章第三段中告诉我们：科学家们开始关注臭氧层是在20世纪80年代中期，所以A项（自从1980年起）、B项（从去年冬天起）、D项（大约一年）都不正确，只有C项符合题意，故选之。 2．根据文章第二段第一句：…which protects humans from harmful levels of ultraviolet radiat ion, …（臭氧层）保护人类免受有害的紫外线的辐射……这一定语从句可以明显地看出臭氧层的作用为D项。 3．本题为事实辨认题。第三段的第一句很清楚地告诉我们：科学家们在20世纪80年代中期，发现了南极上空的臭氧层里的空洞。故选B项为正确答案。 4．本题可采用排除法解。A项文中并未提及，显然可以排除；C、D两项只是原因的一个方面，较为片面，也可排除；惟有B项是对C、D两项的综合，故选之。而且，根据第三段最后一句也可得出B项为正确答案。 5．文章最后一段告诉我们：尽管许多国家已经开始停止使用破坏臭氧层的化学物质，但仍希望发现新的替代品把全面禁止这种化学物质推向一个新台阶。可见，破坏臭氧层的化学物质并没有完全被停止，A项与文中事实不符，故选之。 |
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