---Where’s Lucy?---I’m not sure. She in the school library.A. maybeB. must beC. may beD.

问题补充：

---Where’s Lucy?

---I’m not sure. She in the school library.

A. maybe

B. must be

C. may be

D. will be

答案：

A. maybe

B. must be

(答案→)C. may be

D. will be

解析：may be表示把握性不大的推测，must be是肯定性推测，根据句意选C