【题目】----Catherine, I have cleaned the room for you.
---- Thanks. You _______ it. I could manage it myself.
A. needn’t have done B. needn’t do
C. mustn’t do D. shouldn’t have done
在线课程【答案】A
【解析】
试题分析：考查固定用法。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.