Question

【题目】阅读理解。

Every year there are changes in climate in different parts of the world.Some of these changes are due to natural causes.However,some climate changes are caused by air pollution and these changes may increase.

If the pollution affects the level of carbon dioxide in the atmosphere,the results are likely to be serious.There is only a small part of carbon dioxide in the atmosphere.But it has an important function in keeping the balance between radiation from the sun entering the atmosphere and radiation leaving the Earth.Some of the radiation is absorbed by the Earth and some is radiated back into the atmosphere.The carbon dioxide in the atmosphere prevents some of the radiation from leaving the atmosphere.Thus the heat remains in the atmosphere and carbon dioxide helps to prevent the temperature of the Earth from falling.

If the proportion(比例)of carbon dioxide in the atmosphere is increased as a result of air pollution,the temperature of the atmosphere may rise.This might cause the ice in the North and South to melt.If this happened,the sea level could rise and parts of the Earth would be flooded.This is not quite likely but the possibility exists.

There is also a fairly strong possibility that the dust level in the atmosphere will rise as a result of industrial pollution.This dust pollution will reflect sunlight back onto space.If this happens,less sunlight will reach the Earth and the temperature will fall.

Another danger comes from the destruction(破坏)of the Earth’s vegetation(植物)such as the forest of Brazil,which is being cleared away for farmland and cities.Trees use carbon dioxide and their destruction may upset the balance of carbon dioxide in the atmosphere.

【1】The main purpose of the passage is to tell us that .

A.the climate of the earth is always changing

B.air pollution has greatly affected the climate of the world

C.carbon dioxide has something to do with climate changes

D.the climate of the world is subjected to(使受到)dangers from air pollution

【2】From this passage we learn that carbon dioxide .

A.helps to prevent the temperature of the Earth from rising

B.keeps much of the sun’s radiation from entering the atmosphere

C.plays an important part in keeping the balance of the temperature of the Earth

D.is one of natural causes of climate changes

【3】Judging from this passage,if the level of carbon dioxide in the atmosphere went down,the temperature of the Earth would .

A.become higher B.either rise or fall

C.become lower D.neither rise nor fall

【4】Which of the following is not the possible serious outcome if air pollution is related to climate changes?

A.Parts of the Earth would be flooded one day.

B.More sunlight would reach the Earth.

C.The temperature of the Earth might rise.

D.The Earth’s vegetation might be destroyed.

Answer 1

【答案】

【1】D

【2】C

【3】C

【4】B

【解析】

试题分析：

【1】由第一段最后一句“However,some climate changes are caused by air pollution and these changes may increase.”可知,答案为D项。

【2】根据第二段“There is only a small part of carbon dioxide in the atmosphere.But it has an important function in keeping the balance between radiation from the sun entering the atmosphere and radiation leaving the Earth.”这一信息可知,正确答案为C项。

【3】根据文章第二段“The carbon dioxide in the atmosphere prevents some of the radiation from leaving the atmosphere.Thus the heat remains in the atmosphere and carbon dioxide helps to prevent the temperature of the Earth from falling.”这一信息可知,C项正确。

【4】根据文章倒数第二段“If this happens,less sunlight will reach the Earth...”可知,B项错误。