Sorry Cathy I didn’t know that you were badly short of money then.But you me for help.A.

问题补充：

Sorry，Cathy，I didn’t know that you were badly short of money then.But you me for help.

A. must have asked

B. could have asked

C. would have asked

D. may have asked

答案：

A. must have asked

B. could have asked

C. would have asked

D. may have asked

解析：B

解析考查情态动词。说话人为自己不知道Cathy当时急需用钱而感到抱歉，认为Cathy当时本来可以向自己求助。could have done表示过去本来可以做某事，可实际上并没有做。