单选题
There was one thought that air pollution affected only the
area immediately around large cities with factories and heavy automobile
traffic. At present, we realize that although these are the areas with the worst
air pollution, the problem is literally worldwide. On several occasions over the
past decade, a heavy cloud of air pollution has covered the east of the United
States and brought health warnings in rural areas away from any major
concentration of manufacturing and automobile traffic. In fact, the very climate
of the entire earth may be infected by air pollution. Some scientists consider
that the increasing concentration of carbon dioxide in the air resulting from
the burning of fossil fuels (coal and oil) is creating a "greenhouse
effect"—conserving heat reflected from the earth and raising the world's average
temperature. If this view is correct and the world's temperature is raised only
a few degrees, much of the polar ice cap will melt and cities such as New York,
Boston, Miami, and New Orleans will be in water. Another view,
less widely held, is that increasing particular matter in the atmosphere is
blocking sunlight and lowering the earth's temperature—a result that would be
equally disastrous. A drop of just a few degrees could create something close to
a new ice age, and would make agriculture difficult or impossible in many of our
top farming areas. Today we do not know for sure that either of these conditions
will happen (though one recent government report drafted by experts in the field
concluded that the greenhouse effect is very possible). Perhaps, if we are lucky
enough, the two tendencies will offset each other and the world's temperature
will stay about the same as it is now. Driven by economic profit, people neglect
the damage on our environment caused by the "advanced civilization". Maybe the
air pollution is the price the human beings have to pay for their development.
But is it really worthwhile?
单选题
As pointed out at the beginning of the passage, people used to think
that air pollution ______.
A. Caused widespread damage in the countryside
B. affected the entire eastern half of the United States
C. had damaged effect on health
D. existed merely in urban and industries areas
【正确答案】
D
【答案解析】[解析] 由第一段第一句话可推知。
单选题
As to the greenhouse effect, the author ______.
A. shares the same view with the scientists
B. is uncertain of its occurrence
C. rejects it as being ungrounded
D. thinks that it will destroy the world soon
【正确答案】
B
【答案解析】[解析] 第一段最后一句“If this view is correct...”表明作者只是引用这种现象并不确定其正确性。
单选题
The word "offset" in the second paragraph could be replaced by ______.
A. slip into
B. make up for
C. set up
D. catch up with
【正确答案】
B
【答案解析】[解析] offset补偿；slip into滑入；make up for弥补；set up建立；catch up with赶上。
单选题
It can be concluded that ______.
A. raising the world's temperature only a few degrees would not do much harm
to life on earth
B. lowering the world's temperature merely a few degrees would lead many
major farming areas to disaster
C. almost no temperature variations have occurred over the past decade
D. the world's temperature will remain constant in the years to
come
【正确答案】
B
【答案解析】[解析] 根据第二段第二句话“A drop of just a few degrees...”可推知。