Stay awake! You should know that it to sleep in class.
A. doesn’t permit
B. is not permitted
C. will not be permitted
D. was not permitted
网友回答
A. doesn’t permit
(答案→)B. is not permitted
C. will not be permitted
D. was not permitted
解析：句意：保持清醒！你应该知道在课堂上睡觉是不被允许的。题目中it作为形式主语，后面的不定式作为真正的主语，用一般现在时态的被动形式，故选B