—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：句子的语境是：“我自己能做”，所以“你本不必做的”。选A还是B呢？根据前面一句中的 have cleaned 可知，动作已经发生，所以此处谈论的是一个过去情况，故选 needn’t have done。