----Will Barbara come to our party?--I am not sure because he go to the concert with

问题补充：

----Will Barbara come to our party?

----I am not sure, because he go to the concert with his friend.

A. can

B. must

C. should

D. might

答案：

A. can

B. must

C. should

(答案→)D. might

解析：考察情态动词。A可能；B一定；C应该；D也许；结合句意可知D正确。句意：—芭芭拉要来我们聚会吗？—我不敢肯定。因为他也许和朋友去听音乐会。