It was so nice of you to come to our aid. I don’t think we it without you.A. can manageB.

问题补充：

It was so nice of you to come to our aid. I don’t think we it without you.

A. can manage

B. could have managed

C. must have managed

D. could manage

答案：

A. can manage

(答案→)B. could have managed

C. must have managed

D. could manage

解析：句意：你能来帮助我们真是太好了，我认为没有你我们不可能已经完成它。Could have done:可能已经做了某事 must have done:一定已经做了某事 根据句意可知表达一种对过去情况进行虚拟，故用could/would/might/should+have done。故选B。