— The window must have taken you quite a lot of time that day. — Right. They for weeks.A.

问题补充：

— The window must have taken you quite a lot of time that day.

— Right. They for weeks.

A. haven’t been cleaned

B. hadn’t been cleaned

C. didn’t clean

D. haven’t cleaned

答案：

A. haven’t been cleaned

(答案→)B. hadn’t been cleaned

C. didn’t clean

D. haven’t cleaned

解析：考查时态。句意：那天擦窗户一定花了你很长时间吧。是的，他们已经好几周没擦了。must have taken表示的是对去事情肯定的推测，在这之前发生的动作应用过去完成时态。所以选B。