—That must have been a lot of work.—Yeah it us three days to finish it.A. takes　B. had t

问题补充：

—That must have been a lot of work.

—Yeah, it us three days to finish it.

A. takes

B. had taken

C. took

D. was taking

答案：

A. takes

B. had taken

(答案→)C. took

D. was taking

解析：考查动词时态。句意：——你们一定做了许多工作。——是的，完成这些工作花费了我们三天的时间。根据“must have been”可知，此处是对过去情况的一种推测，故“花费”这一动作应发生在过去，所以用一般过去时。