---I rang you yesterday afternoon. A man answered but I didn’t recognize the voice.Oh

问题补充：

---I rang you yesterday afternoon. A man answered, but I didn’t recognize the voice.

--- Oh, it my uncle. He was in my room then.

A. must have been

B. should have been

C. must be

D. should be

答案：

(答案→)A. must have been

B. should have been

C. must be

D. should be

解析：考查情态动词表推测。因为是对过去事实表推测，要用情态动词加完成时态，排除C,D；should have been表本应该是实际不是；must have been肯定是；根据He was in my room then，可知是我叔叔的可能性很大。所以选A。