Infinitives are forms like (to) write and (to) read. Infinitives are generally used with the marker to. Note that this to is not a preposition; after the preposition to we use –ing forms.
- I would like to meet the manager.
- Is there anything to eat?
- The main thing is to stay calm.
Negative Infinitives are normally formed by putting not before the infinitive.
- I decided to invite them. (affirmative)
- I decided not to invite them. (negative )
- You were silly not to have locked the car. (NOT You were silly to not have locked the car.)