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Verbs

Infinitives in the English Grammar

Infinitives are a key part of English grammar. They can be used in various forms like nouns, adjectives, and adverbs. In this article, you will learn what an infinitive is and how to use it effectively in your sentences. The main sections covered include infinitives as nouns, adjectives, and adverbs.

You’ll also understand when to use infinitives, such as to indicate the purpose of an action or as the subject of a sentence. Additionally, examples and images will illustrate how to use infinitives correctly. You’ll find an infinitive verb list to deepen your knowledge.

What Is An Infinitive?

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Infinitives – Created by 7ESL

Infinitives as Nouns

Keep in mind that a noun can be a person, place, or thing. When used as a subject or direct object in a sentence, an infinitive phrase acts as a noun. In such a case, the subject assumes the role of a verb, whereas the direct object is the receiver of the action of a verb.

Example:

  • I like to watch movies alone.

Here “like” is the verb.

“To watch” is the infinitive as it receives the action of the verb (to be liked).

“To watch” acts as a direct object of the sentence.

Here, the infinitive acts as a noun that expresses a thought.

  • To join hands with others is necessary.

In this sentence, “is” is the verb and “to join” is the infinitive as it answers the question about what is so necessary?

Here the infinitive phrase “to join” is the subject of the sentence.

This is an indication that the infinitive acts as a noun in this example.

Infinitives as Adjectives

An adjective is a word that describes more information about a noun. An infinitive acts as an adjective if it modifies or describes a noun in a sentence.

Example:

  • Joyce needs a table to read on.

Here “needs” is the verb, and “table” is the subject (noun).

“To read” is the infinitive, and it acts as an adjective.

Infinitives as Adverbs

An adverb is a word that modifies or describes an adjective, verb, or an adverb. It provides additional information regarding an adjective, verb, or adverb. At times, adverbs can answer the question “why.”

Here is an example:

  • The mourners were surprised to hear that the deceased had resurrected.

Here “to hear” is the infinitive. It gives additional information about the adjective “surprised.”

When to Use Infinitives

To indicate the purpose of an action:

  • He bought some flowers to give to his wife.
  • I will lock the door to prevent theft.

As the subject of the sentence:

  • To wait seemed foolish when decisive action was required.
  • To swim in that sea may be dangerous.

As the direct object of the sentence:

  • I like to write in English.
  • Everyone wanted to go.

As subject complement:

  • His ambition is to fly.
  • What is essential is to maintain a healthy diet.

As an adjective:

  • This is the best time to practice.
  • I have some jeans to wash.

As an adverb:

  • We must observe carefully to understand the situation.
  • I can’t wait to see them.

After an adjective:

  • It is important to be patient.
  • It is wonderful to have close friends.

After an object that is a noun or pronoun referring to a person:

  • Can I ask you to help me with something?
  • I invited a friend to attend the ceremony.

Used with the question word:

  • Do you understand what to do?
  • Tell me when to press the button.
B1 Knowledge Check · 5 questions

Infinitives Practice Quiz (B1-B2)

1 / 5
Q1

Question 1: She decided ___ a new language before travelling abroad.

Question 1 options
'To learn' is correct because infinitives are formed with 'to' + base verb. After verbs like 'decide', English requires the full infinitive (to + base form). 'Learning' is a gerund, 'learned' is past tense, and 'learns' is a conjugated present tense — none of these follow 'decide' correctly.
Q2

Question 2: What is the role of the infinitive in this sentence? 'She went to the store to buy some milk.'

Question 2 options
'To buy' expresses the purpose of going to the store — it answers the question 'Why did she go?' Infinitives used in this way function as adverbs of purpose. They do not describe a noun, act as subjects, or serve as direct objects in this sentence.
Q3

Question 3: Student A: 'Why did you wake up so early today?' Student B: 'I woke up early ___ the first train to the city.'

Question 3 options
'To catch' is correct because the infinitive here expresses purpose — it answers the question 'Why did you wake up early?' This is the standard use of the infinitive as an adverb of purpose. 'Catching', 'caught', and 'catches' do not correctly express purpose in this structure.
Q4

Question 4: This is a great opportunity ___ your presentation skills in front of a large audience.

Question 4 options
'To improve' is correct because after a noun like 'opportunity', an infinitive is used as an adjective to modify and describe that noun. 'Improving' (gerund), 'improved' (past participle), and 'improves' (conjugated verb) do not correctly follow a noun to modify it in this structure.
Q5

Question 5: Match each sentence to the correct grammar label.

Question 5 options
To travel the world is her greatest dream.
He was excited to receive the award.
She has many reports to write before Friday.
His plan is to open a restaurant downtown.
Infinitive as subject
Infinitive as adjective (modifying noun)
Infinitive as subject complement
Infinitive as adverb (modifying adjective)

Select an item on the left, then tap its match on the right.

Infinitives can function as nouns (subject or direct object), adjectives (modifying nouns), adverbs (expressing purpose or modifying adjectives), and subject complements (after linking verbs).

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