Infinitives As Subject, Object and Complement

Infinitives are one of the three major classes of non-finite verbs namely: Gerunds, and Participles. Non-finite verbs are verb forms that do not possess inflectional properties and such they can not be conjugated for person, tense, and number. They are verbs that are treated more like concepts rather than actions or state of beings as it should be. Infinitives are non-finite verbs that are made up of the particle "to" and a verb in its base form—that is, without inflection. For example;

1. To walk

2. To see

3. To live

4. To do

5. To be

Since infinitives are non-finite verbs, it is only natural that they can function as nouns in structures having that their fellow non-finite verbs can perform nominal functions as well. 

As nominal elements, infinitives can function either as subject, object, or complement in structures or sentences.

As Subject

Infinitives or infinitive phrases can function as subjects in sentences or clauses when they are responsible for the actions performed in such expressions. For example;

1. To live is a great gift.

2. To serve is the purpose of humanity.

3. To love is a great gift.

4. To act on stage is my dream.

5. To be happy is a choice.

As object

Infinitives can function as objects in sentences or clauses when they are the recepients or the ones being affected by the actions of a subject. For example;

1. I want to cook.

2. She has to leave.

3. They chose to stay.

4. Madara cares to give.

5. The principal had to run.

As Complements

Infinitives can function as complements in sentences or clauses when they serve the purpose of describing, re-identifying or restating the subject or objects of a structure. Complements are basically elements that describe subjects or objects in structures. Since there are two aspects related to complement namely; subject complement and object complement, we shall discuss them individually.

Subject complement

Infinitives function as subject complement when they serve the purpose of describing the subject of a clause or sentence. For example;

1. It was to learn.

2. They were to speak next.

3. She is to pray.

4. Mr. Kennedy was to fight.

5. The teacher is to blame.

Now the examples above may not sound natural to a second language speaker but they are indeed grammatically permissible. This is another way to conceptualize them. Example 2 could be interpreted as: 'They are' the ones who were supposed 'to speak next'. And as a subject complement, it answers the question: Who are they? Hence it describes.

Object Complement

Infinitives can function as object complements when they serve the purpose of describing, re-identifying or restating the objects in a sentence or clause. For example;

1. He did that to be free.

2. She told them to have fun.

3. Margaret said that to be safe.

4. Mr. President instructed us to party hard.

5. Mayson pushed us to save her.

Just like in the case of subject complements, here is another way to structure the statements. For instance, using Example 2, 'She told them to have fun', 'to have fun' describes the people who were told to have fun—hence it answers the question who? Or, what people?

So these are the various ways in which infinitives can function as subjects, objects, and complements in structures.

Related posts:

• Gerunds as Nouns 
• Direct object, Indirect object, and Object of the Preposition 
• Functions of Nouns in Sentences 
• 'to' infinitive and 'to' preposition: The Difference
• Action Verbs Explained
• Linking Verbs Demystified
• Primary Auxiliary Verbs Explained