题目内容：
[单选题,7.6分]Once environmental damage _________, it takes many years for the system to recover.
A.has done
B.is to do
C.does
D.is done
参考答案：
选择题：[单选题,7.6分]
- 题目分类：河南财经政法大学-会计学-大学英语4
- 题目类型：选择题
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Once environmental damage _________, it takes many years for the system to recover.
A.has done
B.is to do
C.does
D.is done