—Lilyisahappygirl,buttodaysheseemsinabadmood.—Something...

问题详情：

— Lily is a happy girl, but today she seems in a bad mood.

— Something ________ to her.

        A．must happen                            B．should have happened   

        C．could have happened                      D．must have happened

【回答】

D

知识点：虚拟语气与情态动词

题型：选择题