Gerunds after prepositions
When we put a verb after a preposition, we normally use an -ing form, not an infinitive.
- I am fond of watching movies. (NOT I am fond of to
- John was arrested for stealing a policeman's helmet. (NOT ... for to steal ...)
- Can you talk without opening your mouth?
- I am thinking of writing a novel.
- You must abstain from talking to such people.
- We got the job finished by burning the midnight oil.
- We look forward to hearing from you.
To as a preposition
To can be an infinitive marker (e.g. to work, to laugh). It can also be a preposition. When to is a preposition, it is followed by either a noun or the -ing form of a verb, but not normally by the infinitive. Common expressions in which this happens are look forward to, object to, used to, prefer to, get round to, in addition to.
- I look forward to his next visit. (noun)
- I look forward to hearing from you. (NOT I look
forward to hear from you.)
- I prefer the country to the city. (noun)
- I prefer swimming to walking.
- I am used to waiting for buses. (NOT I am used to
wait for buses.)
- They objected to our entering the room.
- I object to working on Sundays.