—Whose exam paper is it? —It______ be Li Lei's. He always forgets to write his name on it. [ ]A
[ ]
题目简介
—Whose exam paper is it? —It______ be Li Lei's. He always forgets to write his name on it. [ ]A
题目详情
—It ______ be Li Lei's. He always forgets to write his name on it.
[ ]
B. must
C. mustn't
D. can't
答案