单选题
It was very kind of you to do the washing-up, but you ______ it.
A. mustn't B. wouldn't have done
C. mightn't have done D. didn't have to do
【正确答案】
D
【答案解析】[解析] 从but并列的前一分句的内容看，后一分句的内容应是“你本不必做的”，为陈述语气。A项不对，其意是“不可以(不应该)做”。B和C选项中动词均为虚拟式，均可排除。D为正确答案，表示“本不必”。