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。