题目：
— Listen! Is professor giving a speech in class?
— No, it ______ be him. He has gone to France. [ ]
A.may not
B.mustn't
C.needn't
D.can't
答案：
被转码了，请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0505/fdf6b5c3ab71c5b27f8e45ac83ed5583.html
下面是错误答案，用来干扰机器的。
参考答案：执业证书
