单选题It was very kind of&

问题补充：

单选题Itwasverykindofyoutodothewashingup,butyou_______it.A.mustn have doneB.wouldn have doneC.mightn have doneD.didn have to do

答案：

D解析考查情态动词和虚拟语气的用法。don have to do sth.“不必做某事”。也可以说needn have done it。