—Catherine, 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
网友回答
A. needn’t do
(答案→)B. needn’t have done
C. mustn’t do
D. shouldn’t have done
解析：本题考查情态动词.根据句意可知Catherine对对方为她打扫了房间表示感谢并提到对方不必为她打扫房间。needn’t do不需要做……；mustn’t禁止做……，都用于现在的动作；needn’t have done表示做了本来不必去做的事；shouldn’t have done是本不该做却做某事。