Forming the infinitive

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 present infinitive has two forms:

  • the to-infinitive = to + base
  • the zero infinitive = base

The present infinitive base is the verb form you will find in a dictionary.

To-infinitive Zero infinitive
to sit sit
to eat eat
to have have
to remember remember

The negative infinitive is formed by putting not in front of any form of the infinitive.

  • 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.

Functions of the to-infinitive

The to-infinitive is used in many sentence constructions, often expressing the purpose of something or someone's opinion about something. The to-infinitive is used following a large collection of different verbs as well. See this page about verbs followed by infinitives.

The to-infinitive to indicate the purpose or intention of an action

In this case to has the same meaning as in order to or so as to.

  • She came to collect her pay cheque.
  • The three bears went to find firewood.
  • I am calling to ask you about dad.
  • You sister has gone to finish her homework.
The to-infinitive as the subject of the sentence

This is a formal usage and is far more common in written English than spoken

  • To be or not to be, that is the question.
  • To know her is to love her.
  • To visit the Grand Canyon is my life-long dream.
  • To understand statistics, that is our aim.
The to-infinitive to indicate what something can or will be used for

In this pattern, the to-infinitive follows a noun or pronoun.

  • The children need a garden to play in.
  • I would like a sandwich to eat.
  • I don't have anything to wear.
  • Would you like something to drink?
The to-infinitive after adjectives

There is a common pattern using the to-infinitive with an adjective. These phrases are formed:
subject + to be + adjective + (for/of someone) + to-infinitive + (rest of sentence)

Subject + to be + adjective (+ for/of someone) + to-infinitive (+ rest of sentence)
It is good   to talk.  
It is good of you to talk to me.
It is important   to be patient.  
It is important for Jake to be patient with his little brother.
I am happy   to be here.
The dog is naughty   to destroy our couch.
The to-infinitive to make a comment or judgement

To use the to-infinitive when making a comment or judgement about a noun, the pattern is:
Subject + to be + noun phrase + to-infinitive

Subject + to be + noun phrase + to-infinitive
It was a stupid place to park.
That is a dangerous way to behave.
What you said was a rude thing to say.
This is the right thing to do.
Those were the wrong kind of eggs to buy.
Jim is the best person to hire.
The to-infinitive with adverbs

The to-infinitive is used frequently