-ing form or infinitive?

Some verbs may be followed by either an infinitive or an -ing form.
The meaning, however, will change accordingly.

He stopped to smoke = he stopped walking to light up
He stopped smoking  = he didn't smoke any more

The verbs that may be followed by either the infinitive or an -ing form are:

advise, allow, attempt
can't bear, begin
continue
forbid, forget
go on
hate
hear
intend
like, love
permit, prefer, propose
regret, remember
see, start, stop
try
watch

Examples:

We don't allow smoking in here = Smoking is not allowed
We don't allow people to smoke