Directions: Read the following passage. Answer the questions according to the information given in the passage
and required words limit. Write your answers on your answer sheet.
If pollution continues to increase at the present rate, formation of aerosols (微粒) in the atmosphere will
cause the start of an ice age in about fifty years' time. This conclusion, reached by Dr S.I. Rassool and Dr S.
H. Schneider, of the united States Goddard space flight center, answers the apparently conflicting questions
of whether an increase in the carbon dioxide content of the atmosphere will cause the earth to warm up or
increasing the aerosol content will cause it to cool down. The Americans have shown conclusively that the
aerosol question is dominant.
Two conservationists (环境保护主义者) have been the possibility that interfering with the environment
might lead to the planet's becoming unbearably-hot or cold. One of these conservationists has now been laid,
because it seems that even an increase in the amount of carbon dioxide in the atmosphere to eight times its
present value will produce an increase in temperature of only 20℃, which would take place over several
thousand years. But the other problem, now seems larger than ever.
Aerosols are collections of small liquid or solid particles (微粒) disappeared in air or some other medium.
The particles are all so tiny that each is composed of only a few hundred atoms. Because of this they can float
in the air for a very long time. Perhaps the most commonly experienced aerosol is industrial smog of the kind
that used to be seen in London in the 1950s and is an even greater problem in Los Angeles today. These
collections of aerosols reflect the sun's heat and thereby cause the earth to cool.
Within fifty years, if no steps are taken to curb the spread of aerosols in the atmosphere, a cooling of the
earth by as much as 3.5℃ seems unavoidable. If that lasts for only a few years it would start another ice age,
and because the growing ice caps at each pole would themselves reflect much of the sun's radiation it would
probably continue to develop even if the aerosol layer were destroyed.
1. According to Rassool and Schneider, what will the global climate be like in 50 years' time? (No more than
five words.)
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2. What might be the cause of the ice age? (No more than 5 words.)
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3. How can the aerosols in the atmosphere cool the earth down? (no more than 5 words.)
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4. What does the passage mainly tell us? (No more than 6 words.)
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