问题补充:
--- He has to finish the experiment today. He must be in the lab,?
---That s quite possible.
A. mustn he
B. won he
C. doesn he
D. isn he
答案:
A. mustn he
B. won he
C. doesn he
(答案→)D. isn he
解析:该题考查反意疑问句中尾句部分的助动词用法,must be结构中的中心词应为be,且He must be in the lab相当于I think he is in the lab,故其尾句部分为isn he。