---Did they have a good time at the party?---Judging by their smiles they have enjoyed t

问题补充：

---Did they have a good time at the party?

---Judging by their smiles, they have enjoyed themselves.

A. might

B. must

C. could

D. would

答案：

A. might

(答案→)B. must

C. could

D. would

解析：考查情态动词用法。Might have done 也许做了某事；must have done一定做了某事；could have done本可以做却未做；would have done会做某事；句意：—在聚会上你玩的开心吗？—从他们的微笑来看，他们一定完的很开心。