English Grammar Test: Gerunds and Infinitives

Avoid is always followed by the -ing form: avoid driving.

Afford is followed by a to-infinitive: can't afford to buy.

Stop to do means you stop one activity in order to do another, here to greet the friend. Stopped saying hello would mean you used to say hello and then quit.

Remember to do refers to a task you must not forget. Remember doing is about a memory of something already done.

The speaker has a memory of an earlier action, so remember + -ing is correct: remember putting. Remember to put would be about a task still to be done.

After a preposition such as in, a verb takes the -ing form: interested in taking.

In look forward to, to is a preposition, not part of an infinitive, so it is followed by -ing: looking forward to seeing.

A to-infinitive expresses purpose: he went there in order to withdraw money. For + base verb is not used for purpose.

Regret doing means you are sorry about something you did in the past: regret being so rude. Regret to is used for bad news you are giving now (We regret to inform you…).

Make + object is followed by the base verb without to: made us write. (In the passive it changes: we were made to write.)

Allow + object is followed by a to-infinitive: allow me to stay. Unlike let, allow does not take the bare base verb.

The pattern is too + adjective (+ for someone) + to-infinitive: too heavy for me to lift.

An activity used as the subject of a sentence takes the -ing form (a gerund): Swimming every day is good…

Suggest is followed by the -ing form (or a that-clause), never by a to-infinitive: suggested going.

Be used to means "be accustomed to", and its to is a preposition, so it is followed by -ing: is used to working. Do not confuse it with used to work, a past habit.