Once environmental damage , it takes many years for the system to recover.

admin2010-06-03  25

问题 Once environmental damage      , it takes many years for the system to recover.

选项 A、had done
B、is done
C、is to do
D、does

答案B

解析 damage与谓语“做”之间是被动关系,所以用is done。
转载请注明原文地址:https://jikaoti.com/ti/nI3MFFFM
0

最新回复(0)