Heknow the answer but I’m not sure.A. maybeB. may beC. mayD. must

问题补充：

Heknow the answer, but I’m not sure.

A. maybe

B. may be

C. may

D. must

答案：

A. maybe

B. may be

(答案→)C. may

D. must

解析：此题考查情态动词的基本用法。句中may表示推测，意思是“可能”。句意：他也许知道答案，但我不确定。