Understanding Infinitives

An infinitive is the base form of a verb. In English grammar, infinitives appear in two different forms: the to-infinitive (e.g., to swim) and the bare infinitive (without to, e.g., swim).

Both forms have specific structural functions in sentences.

1. The To-Infinitive

The to-infinitive consists of the particle to followed by the base form of the verb.

A. To Express Purpose (Why someone does something)

This is also known as the “infinitive of purpose.” It explains the reason for an action.

I went to the market to buy some fresh fruit. (Why did I go? To buy fruit).
She is studying hard to pass the exam.

B. As the Object of a Verb

Many verbs require a to-infinitive as their direct object.

We decided to postpone the meeting.
He promised to call me later.

C. As the Subject of a Sentence (Formal / Rare)

To err is human; to forgive is divine.

Note: In modern English, we usually prefer using a gerund as a subject: Learning English is fun, rather than To learn English is fun.

2. The Bare Infinitive (Infinitive without “to”)

The bare infinitive is simply the base form of the verb without the particle to. It is used in three main contexts:

All true modal verbs (can, could, may, might, must, should, will, would, shall) are followed by a bare infinitive.

You should study harder. (Not: You should to study).
She can speak German.

B. After Causative Verbs: “Make” and “Let”

Causative verbs express that someone causes an action to happen. We use a bare infinitive after the object of make (to force) and let (to permit).

The teacher made us rewrite the essay. (Forced).
My parents let me stay up late on Fridays. (Permitted).

C. After Verbs of Perception (see, hear, watch, feel)

When we perceive a completed action, we follow the object with a bare infinitive.

I saw him cross the street. (I watched the entire action).
We heard her sing a song.

Next, we will explore Verbs Followed by Gerunds or Infinitives to learn which specific verbs trigger each form.

1. The To-Infinitive#