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 forms

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.)