Welcome to a comprehensive exploration of the infinitive—a powerful and versatile element of English grammar. Whether you’re just beginning to understand grammatical terms or seeking a more nuanced understanding for your own writing, this guide will equip you with everything you need to know.
What is an Infinitive?
At its most basic, an infinitive is the base form of a verb, usually preceded by the word “to.” Think of it as the verb in its purest, uninflected state. It doesn’t show tense, and it doesn’t tell us when the action happens. It represents the potential for action.
Simple Infinitive Examples
Here are a few quick examples:
- To run is good exercise.
- I want to learn Spanish.
- She decided to leave.
Notice how “to” + verb creates the infinitive form. These phrases can function as nouns, adjectives, or adverbs within a sentence.
Functions of the Infinitive
The beauty of the infinitive lies in its adaptability. It isn’t just a verb form; it’s a grammatical chameleon. Let’s examine its primary roles:
As a Noun
An infinitive can act as the subject, object, or complement of a sentence, just like a noun.
- To err is human. (Subject of the sentence)
- I love to read. (Direct object of the verb “love”)
- Her ambition is to travel the world. (Subject complement following “is”)
- The best way to succeed is through hard work. (Subject within a prepositional phrase acting as the subject of the sentence)
As an Adjective
Infinitives can modify nouns or pronouns, functioning as adjectives. They often describe the purpose or quality of the noun they modify.
- I need a book to read on the train. (Modifies “book”)
- She has a lot of work to do. (Modifies “work”)
- This is the perfect place to relax. (Modifies “place”)
- He sought a solution to end the conflict. (Modifies “solution”)
As an Adverb
Infinitives can modify verbs, adjectives, or other adverbs, indicating purpose, reason, or result. They often answer the question “why?” or “to what extent?”
- I went to the store to buy milk. (Modifies “went” – why did you go?)
- She is happy to help. (Modifies “happy” – why is she happy?)
- He tried hard to succeed. (Modifies “tried” – why did he try?)
- The water was too cold to swim in. (Modifies “cold” – to what extent was it cold?)
Bare Infinitive & Split Infinitive
While “to” + verb is the standard infinitive form, there are nuances to consider.
Bare Infinitive
The bare infinitive is the base form of the verb without “to.” It typically appears after certain verbs of perception (see, hear, feel), permission (let, allow), and causative verbs (make, have).
- I saw him leave the room.
- She let her children play outside.
- They made him confess.
- We felt the earth tremble.
Split Infinitive
A split infinitive occurs when an adverb is placed between “to” and the verb. For many years, grammarians discouraged this construction, but it’s now widely accepted, especially when it improves clarity.
- He wanted to quickly finish the race. (Splitting avoids awkward phrasing.)
- It is important to carefully consider all options.
While generally acceptable, avoid splitting infinitives unnecessarily. Aim for clear and natural phrasing.
Gerunds vs. Infinitives: A Quick Comparison
Sometimes, you’ll have a choice between using an infinitive or a gerund (a verb acting as a noun, ending in -ing). The choice often depends on the verb governing the phrase.
Consider these examples:
| Infinitive | Gerund |
| I want to travel. | I enjoy traveling. |
| She decided to study abroad. | She is good at studying. |
| They promised to help. | They insisted on helping. |
There aren’t always hard and fast rules, but this table illustrates a common pattern. Verbs like want, decide, promise often take infinitives, while verbs like enjoy, insist on often take gerunds.
Perfect Infinitive & Continuous Infinitive
Beyond the basic infinitive, there are more complex forms that add nuance to meaning.
Perfect Infinitive
The perfect infinitive (to have + past participle) indicates an action completed before the action of the main verb.
- She seems to have finished her work. (The finishing happened before “seems”)
- I appear to have lost my keys.
- He claims to have seen the suspect.
Continuous Infinitive
The continuous infinitive (to be + present participle) emphasizes the ongoing nature of an action.
- He seems to be working very hard.
- She appears to be sleeping.
- The children were expected to be learning a new language.
These forms add layers of meaning and can express complex relationships between actions.
Infinitive Phrases as Objects of Prepositions
Infinitive phrases can function as the object of a preposition, adding detail and complexity to your sentences.
- He went to learn a new skill.
- She has a plan to succeed.
- They have no reason to complain.
- This is a challenge to overcome.
Recognizing this structure allows you to create more sophisticated and nuanced sentences.
Mastering the infinitive unlocks a powerful tool for precise and expressive writing. By understanding its various forms and functions, you can elevate your grammar and communicate with clarity and confidence. It’s more than just a verb form; it’s a key to unlocking the full potential of the English language.