Infinitives
The infinitive is the base form of a verb, used with or without 'to'. Knowing when to use the infinitive — and when to use a gerund instead — is essential for fluency.
What is an infinitive?
The infinitive is the base form of a verb. It appears in two forms: the full infinitive (to + base verb) and the bare infinitive (base verb without 'to').
| Type | Form | Example |
|---|---|---|
| Full infinitive | to + base verb | She wants to leave. |
| Bare infinitive | base verb (no 'to') | He made her wait. She can swim. |
Uses of the full infinitive (to + verb)
1. After certain verbs:
| Verb + infinitive | Example |
|---|---|
| want, need, hope, plan, decide, agree, refuse, offer, promise, manage, expect, learn, forget, seem | She decided to leave. He refused to answer. |
2. To express purpose:
She went to the library to study.
He called to apologise.
3. After adjectives:
It is difficult to understand. I am happy to help. She was surprised to see him.
4. After question words (how, what, where, when):
I don't know what to say. She showed me how to do it.
Uses of the bare infinitive
After modal verbs: can, could, will, would, must, should, may, might
After make and let (causative): She made him apologise. Let me help you.
After perception verbs (see, hear, watch, feel): I saw her leave. We heard him shout.
Split infinitive: Placing an adverb between 'to' and the verb (e.g. 'to boldly go') is called a split infinitive. While widely accepted today, it is best avoided in formal writing.
Tip: After modal verbs, always use the bare infinitive — never add 'to': She can swim ✓, She can to swim ✗.