河南成教 / 大学英语4
正确率：100%
1、
Once environmental damage _ _ _ _ _ _ _ _ _ , it takes many years for the system to recover.
A.has done
B.is to do
C.does
D.is done
Once environmental damage _ _ _ _ _ _ _ _ _ , it takes many years for the system to recover.
参考答案：
佳题速递：