若其后直接跟动词要用动名词

They don’t allow parking. 他们不准停放汽车。

They shouldn’t allow parking here; the street is too narrow. 这儿不该允许停车，马路太窄了。

若其后跟有宾语再加动词则用动名词

Please allow me to add one more point. 请允许我再补充一点意见。

The money will allow you to go abroad for further study. 那笔钱使你能够出国深造。

比较下面两句

We don’t allow eating in the classrooms. 我们不允许在教室吃饭。

We don’t allow students to eat in the classrooms. 我们不允许学生在教室吃饭。

请看下面一道考题(答案选D)：

— Can I smoke here?

— Sorry. We don’t allow _________ here.

A. people smoking                            B. people smoke

C. to smoke                                     D. smoking