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From the first sentence of the passage, we learn that______
A.acid rain has caused air pollution
B.acid rain has caused widespread environmental damage
C.acid, rain has become a much studied subject
D.acid rain travels in all directions before it rains down

A.acid
B.acid
C.acid,
D.acid

【参考答案】

B
第一段第一句指出,酸雨是空气污染的一种形式,由于其所造成的普遍环境损害,最近人们对它展开了激烈的争论。
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