---I do not know why Tom was absent from yesterday meeting.

问题描述:

---I do not know why Tom was absent from yesterday meeting.
---He must been sick ,( )
A.is not he B.was not he C.did not he D.must not he
选第二个,为什么

1、 是昨天不在,因此用过去时.
2、 对于be sick 的提问, 用be动词, 因此 wasn't he? 正确