【题目】---The window must have taken you quite a lot of time that day.
--- You are right. They ________ for weeks.
A.haven't been cleaned
B.hadn't been cleaned
C.didn't cleaned
D.haven't cleaned

【答案】B
【解析】窗户是被擦干净，所以用被动式，只能在AB之间选，根据句意：--那天擦窗户一定花了你很多时间，--对，它们几个星期没擦了。因为那天擦过了，所以用过去完成时。选B。