------Tom is never late for work. Why is he absent today?---Something to him.A. must

问题补充：

------Tom is never late for work. Why is he absent today?

------ Something to him.

A. must have happened

B. can have happened

C. must happen

D. can happen

答案：

(答案→)A. must have happened

B. can have happened

C. must happen

D. can happen

解析：根据句意：汤姆从来不迟到。为什么今天迟到了呢？他肯定是出了什么事。

must have done 过去肯定做了某事，对过去的肯定推测。

对过去的否定推测应用 can’t have done.一般没有B这种形式。C表对现在的推测，不对。