LoginInfinitive Clauses
In this lesson we learn about infinitive clauses, which are essential groups of words that contain an infinitive verb form (to + base verb) and often function as noun phrases. Clear explanations and practice exercises to help you learn.
What Are Infinitive Clauses?
Infinitive clauses are dependent clauses that are formed using an infinitive to indicate the purpose, result, or reason of the action in the main clause. Infinitive clauses can function as nouns, complements, adjectives, or adverbs in a sentence.
Infinitive Clauses: Types
There are two types of infinitive clauses:
To-infinitives
Bare infinitives
To-Infinitives
To-infinitives, as the name suggests, use "to" before the base form of the verb. To-infinitive clauses are dependent clauses introduced by a to-infinitive verb.
If you want to make me happy, buy me flowers.
The boy was lucky to have passed these tests before.
Bare Infinitive
When an infinitive is used without the particle "to", it is called a bare infinitive. Pay attention to the examples:
I made John leave.
Help me open the door.
Infinitive Clauses: Functions
Infinitive clauses can serve as the subjects, objects, **complements, adjectives, or adverb in the sentence. The table below shows the variety of the functions that infinitive clauses can fulfill in a sentence:
To-infinitive | Bare infinitive | |
|---|---|---|
Subject | ✔ | ✘ |
Object | ✔ | ✔ |
Subject complement | ✔ | ✔ |
Adjective complement | ✔ | ✘ |
Adjective | ✔ | ✘ |
Adverb | ✔ | ✘ |
Infinitive Clauses as Subjects
To-infinitive clauses can function as the subject of a sentence. The verb 'be' or other state verbs typically follow the infinitive clause. For example:
To swim after a meal is always wrong.
To be promoted was his dream.
Tip!
The above sentences might sound too formal. It is more common to express these sentences using 'it' as a dummy pronoun, or a participle clause. For example:
Swimming after a meal is wrong.
It is wrong to swim after a meal.
Infinitive Clauses as Objects
Both bare infinitive and to-infinitive clauses can serve as the object of a sentence. Many verbs can be followed by a to-infinitive clause as the direct object. But bare infinitive are usually used as the object of specific verbs, such as causative and permissive (make, have, help, let, etc.) verbs and verbs of perception.
I have decided to go to Iran for the holidays.
basic to-infinitive as object
I regret to have missed the meeting.
perfect to-infinitive as object
He wants to be recognized.
passive to-infinitive as object
They helped us move the furniture.
bare infinitive as object of a causative verb
I watched the bird fly across the sky.
bare infinitive as object of a perception verb
Infinitive Clauses as Subject Complements
Bare and to-infinitive clauses can serve as a subject complement after the verb 'be' or other linking verbs. For example:
My advice is to consult a lawyer at once.
basic to-infinitive as subject complement
His desire was to be acknowledged.
passive to-infinitive as subject complement
What we must do is act quickly.
bare infinitive as subject complement
Infinitive Clauses as Adjective Complements
To-infinitive clauses can act as adjective complements to specify how or why an adjective applies.
She was happy to see her friend.
Modifies the adjective "happy" by explaining the reason for her happiness.
She was proud to have finished the project.
perfect to-infinitive as adjective complement
I was glad to be rewarded for my hard work.
passive to-infinitive as adjective complement
Infinitive Clauses as Adjectives
To-infinitive clauses can be used as adjectives to modify a noun or pronoun. Here are some examples:
This is a place to visit.
basic to-infinitive as adjective
The only person to have finished the project was Sarah.
perfect to-infinitive as adjective
The room to be cleaned is at the end of the hall.
passive to-infinitive as adjective
Infinitive Clauses as Adverbs
To-infinitive clauses can be used as adverbs to express reason and purpose. For example:
He stayed late to finish the project.
I'd like something to eat for lunch.
He checked his voicemail to see who has called.
He went home early to watch his favorite show.
Infinitive Clauses with Adverbs
Infinitive clauses can also be used with the adverbs 'too' and 'enough' in order to specify a criterion. In these cases, we can easily remove the infinitive and the sentence would still be grammatically correct. Look at the examples:
There is too much salt to put in this soup.
You can say "There is too much salt" and the sentence would be correct.
She's old enough to date whomever she deems suitable.
Infinitive Clauses with Question Words
Verbs such as 'ask, decide, explain, forget, know, show, tell, and understand' can be followed by question words like where, how, what, who, and when followed by the infinitive clause. In these cases, a nominal relative clause is formed which functions as a noun. Take a look at the examples:
My mom asked me how to use the computer.
I'll tell you when to start the process.
He's forgotten where to look for his suitcase.
Review
Infinitive clauses are introduced by a bare infinitive or to-infinitive verb. Infinitive clauses can function as:
Nouns
Complements
Adjectives
Adverbs
Quiz:
Which sentence correctly uses a bare infinitive?
They let the children to play outside.
She made him apologizing for his mistake.
We helped them move the heavy boxes.
He wants to be promoted this year.
Complete the table by selecting the function of the infinitive clause in each sentence.
| Sentence | Function of infinitive clause |
|---|---|
To learn a language takes time. | |
She agreed to help. | |
She called to ask a question. | |
He was relieved to finish the exam. | |
This is a book to read. | |
Her goal is to graduate. |
Which sentence uses a to-infinitive clause as an adjective?
To bake a cake requires patience.
She stayed up late to prepare for the exam.
The instructions to follow are on the desk.
I want to be heard during the meeting.
Sort the words to form a grammatically correct sentence.
Fill the blanks with the correct form of the verbs in parentheses.
She made her brother
(clean) his room before dinner.
He was surprised
(find) his lost keys on the table.
I don’t know when
(start) this project.
We heard the birds
(sing) this morning.
She went to the library
(study) for her exams.
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