问题补充：
--- Hi, Tom. Any idea where Jane is?
--- She in the classroom. I saw her there just now.
A. shall be
B. should have been
C. must be
D. might have been
答案：
A. shall be
B. should have been
(答案→)C. must be
D. might have been
解析：本题考查情态动词。句意为：——喂, 汤姆, 知道简在哪儿吗？——一定在教室里。我刚才在那儿看见过她。由语境可知现在在教室的可能性很大。因此用must。B项和D项表示对过去事情的推测, 不符合语境。shall不用来表推测, 排除A项。
