—Lookatthegirlunderthetree.IsitMary?—It

问题详情：

—Look at the girl under the tree. Is it Mary?

—It ______ be her. I saw her go to the library just now.

               A. must                      B. can’t                 C. could                D. might

【回答】

B

知识点：情态动词

题型：选择题