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

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：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本来不必为她打扫房间。很显然对方打扫房间是过去所为，表达“去不必做某事”用needn’t have done sth.