You have worked for a long time. You be very tired.A. mustB. can’tC. couldD. mustn’t

问题补充：

You have worked for a long time. You be very tired.

A. must

B. can’t

C. could

D. mustn’t

答案：

(答案→)A. must

B. can’t

C. could

D. mustn’t

解析：句意：你已经工作很久了。你一定很累。Must必须；can’t不能，不会，不可能；could能。会；mustn’t禁止，不允许。表示肯定的推测常用must be，所以选A。