-Hi,Sam,is that man our new teacher?-No,it____be Mr Wang.A.might B.can't C.mustn't D.must

问题描述:

-Hi,Sam,is that man our new teacher?-No,it____be Mr Wang.
A.might B.can't C.mustn't D.must

B
必须和No保持一直所以选择否定式.而Mustn't 是禁止的意思