题目内容：
根据下列文章，回答题。
As pointed out at the beginning of the passage．people used to think that air pollution_____
参考答案：
答案解析：
单选题：根据下列文章，回答题。As pointed out at the beginning of the passage．pe
- 题目分类：公共英语三级
- 题目类型：单选题
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As pointed out at the beginning of the passage．people used to think that air pollution_____