题目内容：
根据下列文章，回答题：
In many areas it is required that used batteries be properly disposed of because they ______
参考答案：
答案解析：
单选题：根据下列文章，回答题：In many areas it is required that used batteries
- 题目分类：英语六级
- 题目类型：单选题
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In many areas it is required that used batteries be properly disposed of because they ______