—Catherine I have cleaned the room for you.—Thanks. You it. I could manage it myself. A.

问题补充：

—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

答案：

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。