What Are Infinitives, and How Do You Use Them?

Infinitives are a basic but very important part of English grammar. They are usually formed using “to + base verb”, such as to eat, to learn, or to speak. Infinitives are used to talk about actions, purposes, plans, and intentions, and they appear in many everyday English sentences.

Table of Contents

In this guide, you will learn what infinitives are, the different types of infinitives, and how to use them correctly in sentences. With clear explanations and easy examples, this post will help you understand infinitives step by step and improve both your speaking and writing skills.

This topic is part of our English Grammar for English learners.

What Are Infinitives?

An infinitive is the base form of a verb, usually preceded by the word “to.”

It’s the version of the verb you’ll find in a dictionary.

For example:

To eat
To run
To write

Infinitives can function in several ways within a sentence.

They can act as nouns, adjectives, or adverbs, which I’ll discuss in more detail later.

The key thing to remember is that infinitives express an action or a state of being in a general, non-specific way.

Types of Infinitives

There are two main types of infinitives: the “to-infinitive” and the “bare infinitive.”

To-Infinitive: This is the most common form, where the verb is preceded by “to.”

For example:

- To learn
- To sing
- To travel

Bare Infinitive: This is the base form of the verb without “to.”

It’s used after certain verbs and in specific constructions.

For example:

- Help me carry this.
- She made me laugh.
- Let him go.

Using Infinitives

Infinitives can be used in various ways within sentences.

Let’s explore the different functions they can serve.

Infinitives as Nouns

When infinitives act as nouns, they can be the subject or object of a sentence.

Here are some examples:

Subject:

- To read is important for learning.
- To swim in the ocean is her favorite activity.

Object:

- She likes to dance.
- They decided to stay at home.

In these examples, the infinitive phrases (“to read,” “to swim,” “to dance,” “to stay”) function as the main focus of the sentences, either as the subject performing the action or as the object receiving the action.

Infinitives as Adjectives

Infinitives can also describe nouns, functioning as adjectives.

When used this way, they often provide more information about a noun in the sentence.

For example:

She has a book to read.
This is the best place to relax.
He needs someone to help him.

In these sentences, the infinitive phrases (“to read,” “to relax,” “to help”) modify the nouns (“book,” “place,” “someone”), giving us more details about them.

Infinitives as Adverbs

Infinitives can modify verbs, adjectives, or other adverbs, functioning as adverbs themselves. They often explain why something is done.

For example:

She came to talk.
He worked hard to succeed.
They are eager to learn.

In these sentences, the infinitive phrases (“to talk,” “to succeed,” “to learn”) provide reasons for the actions (“came,” “worked hard,” “are eager”).

Infinitive Phrases

An infinitive phrase consists of the infinitive verb plus any additional words that complete its meaning.

These words might include objects, modifiers, or complements.

For example:

To eat a balanced diet is essential.
They wanted to travel around the world.
She was happy to help with the project.

In these examples, the infinitive phrases (“to eat a balanced diet,” “to travel around the world,” “to help with the project”) provide complete thoughts that add depth to the sentences.

Common Uses of Infinitives

Infinitives are versatile and appear in many common English constructions.

Here are some typical scenarios where you might encounter infinitives:

After Certain Verbs

Many verbs are followed by infinitives.

Here are some examples:

I want to learn.
They agreed to help.
She decided to go.

These verbs (want, agreed, decided) are commonly followed by infinitives, creating a specific meaning or intention.

After Adjectives

Infinitives often follow adjectives to explain why someone feels a certain way.

For example:

I’m happy to see you.
She was eager to start.
They were surprised to hear the news.

In these sentences, the infinitives (“to see,” “to start,” “to hear”) provide reasons for the adjectives (“happy,” “eager,” “surprised”).

To Express Purpose

Infinitives can express the purpose of an action, often indicating why something is done.

For example:

He went to the store to buy milk.
She studied hard to pass the exam.
They traveled to Paris to see the Eiffel Tower.

In these examples, the infinitives (“to buy,” “to pass,” “to see”) explain the purpose of the actions (“went to the store,” “studied hard,” “traveled to Paris”).

Infinitives without “To”

As mentioned earlier, some verbs and expressions are followed by the bare infinitive (without “to”).

Here are some common examples:

Make: She made me laugh.
Let: Let him go.
Help: Can you help me move this?

In these sentences, the verbs (“made,” “let,” “help”) are followed directly by the bare infinitives (“laugh,” “go,” “move”).

Split Infinitives

A split infinitive occurs when an adverb or other word is inserted between “to” and the verb.

While traditional grammar rules advised against splitting infinitives, modern usage has become more flexible.

For example:

She decided to quickly leave.
He wants to really understand the problem.

In these examples, the adverbs (“quickly,” “really”) are placed between “to” and the verb (“leave,” “understand”), creating split infinitives.

While some people still prefer to avoid split infinitives, they are generally accepted in contemporary writing and speech, especially when they improve clarity or flow.

Infinitives in Questions and Negatives

Infinitives also appear in questions and negative sentences.

Here are some examples:

Questions:

- What do you want to do?
- Where would you like to go?

Negatives:

- I decided not to go.
- She asked him not to tell anyone.

In these sentences, the infinitives (“to do,” “to go,” “to go,” “to tell”) are used within questions and negative constructions to convey specific actions.

Common Mistakes with Infinitives

Learning how to use infinitives correctly takes practice.

Here are some common mistakes and tips to avoid them:

Using the wrong form of the verb:

- Incorrect: She wants going to the park.
- Correct: She wants to go to the park.

Forgetting to use “to” with certain verbs:

- Incorrect: I decided go to the store.
- Correct: I decided to go to the store.

Splitting infinitives unnecessarily:

- Incorrect: She decided to carefully read the instructions.
- Correct: She decided to read the instructions carefully.

Note: While this isn’t always wrong, it’s best to avoid splitting infinitives unless it improves clarity or emphasis.

Practice Exercises

To help solidify your understanding of infinitives, here are some practice exercises.

Try to fill in the blanks with the correct infinitive form of the verb in brackets.

She plans _______ (travel) to Europe next summer.
They hope _______ (finish) the project by tomorrow.
He offered _______ (help) with the preparations.
She was excited _______ (start) her new job.
We need _______ (find) a solution quickly.

Answers:

to travel
to finish
to help
to start
to find

Conclusion

Infinitives are super important in English grammar because they help us show actions, goals, and reasons in sentences.

When you learn to use infinitives the right way, it can really boost your writing and speaking abilities, making what you say clearer and more powerful.

FAQs on Infinitives

Q1. What is an infinitive in English grammar?
An infinitive is the base form of a verb, often preceded by “to,” such as to eat, to run, to write. It can function as a noun, adjective, or adverb in a sentence.

Q2. What are the two types of infinitives?
The two types are:

To-infinitive (e.g., to learn, to play).
Bare infinitive (the verb without “to,” used after certain verbs like make, let, help).

Q3. Can infinitives be used as subjects in a sentence?
Yes. Example: To read is important. Here, to read is the subject.

Q4. What is the difference between an infinitive and a gerund?

An infinitive uses the base form of the verb with to (e.g., to dance).
A gerund uses the -ing form of the verb and acts like a noun (e.g., dancing).

Q5. When do we use bare infinitives?
Bare infinitives are used after verbs like make, let, and sometimes help. Example: She made me laugh.

Q6. Are split infinitives grammatically wrong?
Traditionally, they were avoided, but in modern English, split infinitives (e.g., to really understand) are acceptable, especially if they make the sentence clearer.

Q7. How do infinitives express purpose?
Infinitives show purpose when they explain why something is done. Example: She studies hard to pass the exam.

Q8. What are common mistakes with infinitives?

Forgetting to (e.g., ❌ I decided go → ✅ I decided to go).
Using the wrong form (e.g., ❌ She wants going → ✅ She wants to go).

Q9. Can infinitives come after adjectives?
Yes. Example: I am happy to help. Here, to help follows the adjective happy.

Q10. Why are infinitives important in English learning?
Infinitives help learners express actions, intentions, and purposes clearly, making both writing and speaking more natural and fluent.