--Catharine,I have cleaned the room for you.--- Thanks.You ________ it.I could manage it myself.A needn’t do B.needn’t have done C.mustn’t do D.shouldn’t have done为何不选A
问题描述：
--Catharine,I have cleaned the room for you.--- Thanks.You ________ it.I could manage it myself
.A needn’t do B.needn’t have done
C.mustn’t do D.shouldn’t have done
为何不选A
答
情态动词+动词原形,描述现在的事情
情态动词+have done,描述过去的事情
打扫是过去的事情了,B翻译为你本没有必要做的（实际上已经做过了）