--Where is Xiao Wang?--I dont know. He be in the library.A. canB. mustC. mightD. may

问题补充：

--Where is Xiao Wang?

--I don know. He be in the library.

A. can

B. must

C. might

D. may

答案：

A. can

B. must

(答案→)C. might

D. may

解析：might表示毫无把握的猜测。can比may的肯定性要稍微大一些，must为实事肯定。