问题
选择题
It was very kind of you to do the washing up, but you _______ it.
A.mustn't have done
B.wouldn't have done
C.mightn't have done
D.didn't have to do
答案
D
考查情态动词和虚拟语气的用法。don't have to do sth.“不必做某事”。也可以说needn't have done it。