3.-What do you think the noise was? --It ___________ a cat. A.may be B.might be
问题描述：
3.-What do you think the noise was? --It ___________ a cat. A.may be B.might be C.could have been D.might have been
D 为什么B不可以啊?
答
情态动词表推测时他们的过去式并不表示过去发生的事,情态动词对过去的推测的结构通常都是could/should/might+have done