单项选择题

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 damaging effects on health
D．existed merely in urban and industrial areas

<上一题目录下一题>

热门试题

单项选择题

As far as the greenhouse effect is concerned, 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

单项选择题

It can be inferred from the passage 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