1. What is an infinitive?
An infinitive is a verb that functions as a noun, adjective, or adverb in order to express an opinion, purpose of an object or action, or answer the questions who, what, or why.
An infinitive usually begins with the word “to” and is followed by the base form of a verb (the simple form of the verb that you would find in the dictionary).
Examples of infinitives include to read, to run, to jump, to play, to sing, to laugh, to cry, to eat, and to go.
Remember that although infinitives are verbs, they do not function as verbs, instead they are used as nouns, adjectives, or adverbs. Let’s look at some examples.
Infinitives as Nouns
Remember that a noun is a person, place, or thing. When an infinitive is used as the subject or direct object in a sentence, it functions as a noun.
The sentence’s subject performs the verb, while the sentence’s direct object receives the verb.
I love to sleep.
- In this sentence, the verb is “love.”
- Who or what receives the action of being loved? The infinitive “to sleep.”
- This makes “to sleep” the direct object of the sentence.
- In this case, the infinitive functions as a noun that expresses an opinion. It could be replaced with a person, place, or thing, as in, “I love pizza.”
To help others is so important.
- In this example, we have the verb “is.”
- Who or what is so important? The infinitive “To help.”
- In this case, the infinitive “to help” is the sentence’s subject.
- This means that the infinitive functions as a noun in this sentence.
2. Examples of Infinitives
I really need to eat something.
- In this sentence, the verb is “need.”
- Who or what do I need? The infinitive “to eat.”
- “To eat” is the direct object of “need” because it receives the action.
- This is an example of an infinitive being used as a noun.
We can’t play until we find a ball to throw.
- What is the purpose of the infinitive “to throw” in this sentence?
- It describes the noun “ball.” We don’t need just any ball, we need a ball “to throw.”
- Here, the infinitive is used as an adjective.
Brenda left the camping trip early to recover from poison ivy.
- The infinitive in this example is “to recover.”
- What is the purpose of “to recover” in this sentence?
- It gives us more information about why Brenda left the trip early. It modifies the verb “left.”
- In this example, the infinitive functions as an adverb.
Mom made my brother clean his room.
- This sentence uses the verb “made,” followed by the direct object “brother.”
- When the verb “made” is followed by an infinitive, the infinitive loses the “to.”
- It would be incorrect to write, “Mom made my brother to clean,” or, “Mom made to clean.”
- For this reason, the direct object is followed by the infinitive “clean” without the “to.”
3. Infinitives as Adjectives
An adjective is a word that modifies (adds to or describes) a noun. So infinitives function as adjectives when they modify or describe nouns in a sentence.
Joel wants a book to read.
- In this sentence, the verb is “wants” and the subject is the noun “book.”
- We also see the infinitive “to read.” What is the purpose of “to read” in this sentence?
- It describes the book; Joel isn’t looking for just any book, he’s looking for a book to read.
- In this sentence, the infinitive functions as an adjective.
4. Infinitives as Adverbs
Adverbs modify or describe adjectives, verbs, or other adverbs. They provide additional information about what, where, how, and to what extent or degree. Sometimes adverbs also answer the question, “Why?”
Infinitives function as adverbs when they are used to give more information about adjectives, verbs, or other adverbs in the sentence.
The students were excited to go on a field trip.
- In this sentence, the infinitive is “to go.”
- What is the purpose of “to go” in this sentence?
- The infinitive “to go” gives us more information about the adjective “excited”; it tells us what the students were excited about (going on a field trip).
- In this case, the infinitive functions as an adverb.
Mom is going to the store to buy dinner.
- In this sentence, the infinitive is “to buy.”
- What’s the purpose of “to buy” in this example?
- The infinitive “to buy” gives us more information about the verb “going”; it tells us why Mom is going to the store (to buy dinner).
- This is another example of how infinitives can function as adverbs.
5. Infinitives Without “To”
Almost always, infinitives begin with “to.” But infinitives lose the “to” when they follow these verbs:
These verbs are followed by a direct object, then by an infinitive without the “to.”
When I heard the alarm clock ring, I knew it was time to get up.
- This sentence uses the verb “heard” followed by the direct object, “alarm clock.”
- When infinitives follow the verb “heard,” they lose the “to.” We wouldn’t say, “I heard the alarm clock to ring,” or, “I heard to ring.”
- So, “alarm clock” is followed by the infinitive “ring” without the “to.”
- For this reason, this sentence correctly uses the infinitive without the “to.”
My mom helps me do my homework.
- This sentence uses the verb “helps” followed by the direct object “me.”
- When infinitives follow “helps,” they drop the “to.” In English, it doesn’t sound correct to write, “My mom helps me to do my homework,” or, “My mom helps to do.”
- So, “me” is followed by the infinitive “do” without the “to.”
- This is another correct example of using an infinitive without the word “to.”
6. Can You Split Infinitives?
Usually, no other word should come between “to” and the base verb that follows it. When this does happen, you get a split infinitive.
For example, you might say:
Ryan hopes to quickly eat his dinner so he won’t miss his favorite show.
In this case, the word “quickly” splits the infinitive “to eat.”
Some English teachers will tell you that you should never split an infinitive, while others might tell you that it’s okay, especially in informal writing. When in doubt, simply avoid splitting the infinitive.
In the example above, you could avoid splitting the infinitive by instead writing:
Ryan hopes to eat his dinner quickly so he won’t miss his favorite show.
Remember that infinitives are formed with the word to + the base form of a verb. Although infinitives are formed using verbs, they don’t function as verbs in a sentence. Instead, infinitives can function as nouns, adjectives, or adverbs.