--The man in a black suit be our youth worker.I’m sure it be him. I saw him in the l

问题补充：

--The man in a black suit be our youth worker.

--- I’m sure it be him. I saw him in the laboratory building some minutes ago.

A. must; can’t

B. can; mustn’t

C. can; could

D. must; won’t

答案：

(答案→)A. must; can’t

B. can; mustn’t

C. can; could

D. must; won’t

解析：句意：那个穿黑色西装的人肯定是我们的青少年辅导员。我确定不可能是他，我几分钟前看到他在实验楼里。must肯定; can’t不可能，故选A