问题补充:
-----The windows must have taken you quite a long time that day.
------Right. Theyfor 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:考察时态。根据must have taken you quite a long time可知,这是对过去的推测,所以没有打扫是发生在花很长时间打扫这个动作之前,即过去的过去。