The teacher doesn't permit ___ in class.
允许permit[动词verb]一件事或人doing something/somebody[名词Noun]
答案：名词 (noun)
A. smoke (verb)
B. smoking (noun)
C. to smoke (去抽 - 动作）强调要抽了.
example: I am going to smoke. (我要抽烟了.）
D. to have a smoke ( 去抽烟 ）强调要抽烟.
example: I am going to have a smoke (我要去抽烟.）
虽然选项都是关于抽烟,在语法上的运用是有差异的.
因为英文与华文在语法与词义方面有异,以上的例句可能无法表达真确的语气.请多多见谅.