The infinitive is the base form of a verb. In English, when we talk about the infinitive we are usually referring to the present infinitive, which is the most common. There are, however, four other forms of the infinititive: the perfect infinitive, the perfect continuous infinitive, the continuous infinitive, & the passive infinitive.
the to-infinitive = to + baseThe present infinitive has two forms:
the zero infinitive = base
Examples
I decided not to go to London.
He asked me not to be late.
I'd like you not to sing so loudly.
I'd rather not eat meat.
I might not come.