阅读理解Everyyeartherearechangesinclimateindifferentpartsoftheworld.Someofthesechangesareduetonaturalcauses.However,someclimatechangesarecausedbyairpollutionandthesechangesmayincrease.I

Question

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 (二氧化碳) in the atmosphere, the results are likely to be serious. Carbon dioxide has only a small part of 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 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 the South to melt. If this happened, the sea level could rise and parts of the Earth would be flooded, This happening 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 hack into space. If this happens less sunlight will reach the Earth and the temperature will fall.

Another danger comes from the destruction of the Earth’s vegetation (植物) such as the forests of Brazil, which are 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 this passage is to tell us that ________.

[　　]

A．the climate of the world is always changing

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

C．carbon dioxide has something to do with climate dangers

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 Earthwould ________.

[　　]

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 outcomes of air pollution related to climate changes?

[　　]

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

B．Less sunlight would reach the Earth.

C．The temperature of the Earth might rise.

D．The Earth’s vegetation might be destroyed.

5．It is obvious that the author ________.

[　　]

A．is for the opinion that the climate changes are due to natural causes

B．afraid that air pollution will greatly change the climate of the would

C．hopes that more studies should be made on the worlds’s climate

D．suggests that steps be taken to prevent the destruction of the Earth’s vegetation

Answer 1

D;C;C;A;B