Infinitive Phrase

An INFINITIVE PHRASE is a phrase Opens in new window that contains an infinitive Opens in new window plus any complements Opens in new window and modifiers Opens in new window.

For example survey the following sentence Opens in new window.

  • √  To kill the thief is unlawful.

In the sentence the group of words in bold is an infinitive phrase because the infinitive, to kill, has the added words, the thief.

Ponder another example below.

  • √  It is not good to eat all the eggs.

The group of words to eat all the eggs is an infinitive phrase as a result of the added words, all the eggs, to the infinitive, to eat.

Now, within the remainder of this study, we will be exploring the grammatical functions of infinitive phrases under the following headings.

1.  Infinitive Phrases used as Noun Phrases

An infinitive phrase is considered a noun phrase Opens in new window only if it is serving as a subject Opens in new window, a direct object Opens in new window, an indirect object Opens in new window, or a predicate nominative Opens in new window.

1.1  Infinitive Phrases as Subjects

Survey the following sentences.

  • To sleep on top of a tree is very relaxing.
  • To study during the night can be rewarding.
  • To speak to a crowd of thousand without a microphone needs much energy.
  • To pay the price of success is unrealistic for most entrepreneurs.
  • To play with the kids is her newly found leisure.

The infinitive phrases in bold type in these sentences Opens in new window are acting as subjects because they are performing the actions in the sentences. Now, since they are performing the subject Opens in new window role, they are nouns Opens in new window.

Important Hint!  

It’s important to note that the grammatical name of each of the words (in bold) above is infinitive phrase as a noun phrase, and the grammatical function is that each is the subject of the verb Opens in new window in its sentence.

    Thus, we can say of the words in bold in
  • To sleep on top of a tree is very relaxing.
  • as To sleep on top of a tree is an infinitive phrase (or noun phrase) acting as the subject of the verb is. The same is true of the remaining sentences Opens in new window above.

1.2  Infinitive Phrases as Direct Objects

Ponder each of the sentences below.

  • Every baby needs to crawl in his early age.
  • You deserve to succeed for being hardworking.
  • Gretchen loves to dance in birthday parties.
  • The man Jesus came to die for us that we might live.
  • Everybody should work to support the new administration.

The infinitive phrases in bold type in these sentences are acting as direct objects Opens in new window because they immediately follow the action verbs Opens in new window in the sentences, which implies that they are receiving the actions in the sentences Opens in new window. Now, since they immediately follow the action verbs Opens in new window, they are nouns Opens in new window.

Important Hint!  

Note that the grammatical name of each of the infinitives above is infinitive phrase as a noun phrase, and the grammatical function is that each is serving as the direct object of the verb in its sentence.

    Thus, we can say of the words in bold type in
  • Every baby needs to crawl in his early age.
  • as to crawl in his early age is an infinitive phrase (or noun phrase) acting as the direct object of the verb needs. The same is true of the remaining sentences above.

1.3  Infinitive Phrases as Direct Object Following Indirect Objects

Ponder also the following sentences.

  • He called her to dance before the chief.
  • They caused him to weep unstoppably.
  • They called their father to come home very soon.
  • Her mother forced her to to swear an oath.
  • Nobody challenged him to leave the house.

The infinitive phrases in bold type in these sentences are acting as direct objects Opens in new window because they immediately follow the indirect objects Opens in new window in the sentences, which implies that they are receiving the actions in the sentences. Now, since they immediately follow the indirect objects, they are noun phrases Opens in new window.

Important Hint!  

Remember that the grammatical name of each of the infinitives Opens in new window above is infinitive phrase acting as a noun phrase (or simply, noun phrase), and the grammatical function is that each is serving as the direct object of the verb in its sentence Opens in new window.

    Thus, we can say of the words in bold in
  • He called her to dance before the chief
  • as to dance before the chief is an infinitive phrase (or a noun phrase) acting as the direct object of the verb called. Same must be said of the remaining sentences above.

1.4  Infinitive Phrases as Predicate Nominatives

Again, let's survey the following sentences.

  • The best thing needed in your life is to fear God.
  • Her wish is to succeed in life.
  • Your destiny must be to eliminate poverty in this world.
  • Her duty now has been to sweep at the compound and in the kitchen.
  • His dream is to empower the youth going into businesses.

The infinitive phrases in bold type in these sentences are acting as predicate nominatives Opens in new window because they immediately follow the linking verbs Opens in new window in the sentences. Now, since they immediately follow the linking verbs, they are noun phrases Opens in new window.

Important Hint!  

Notice that the grammatical name of each of the infinitive phrases above is infinitive phrase acting as a noun phrase, and the grammatical function is that each is serving as the predicate nominative of the verb in its sentence.

    Thus, we can say of the words in bold in
  • The best thing needed in your life is to fear God
  • as to fear God is an infinitive phrase (or a noun phrase) acting as the predicate nominative of the verb is. Again, the same is true of the remaining sentences above.

2.  Infinitive Phrases used as Adjective Phrases

An infinitive phrase is considered an adjective phrase Opens in new window only if it immediately follows a noun. For example, survey the sentence below.

  • √  I had a tendency to doze in public.

We understand that the infinitive phrase, to doze in public, immediately follows the noun, tendency. This implies that to doze in public is modifying the noun, tendency. And we know that only adjectives Opens in new window modify nouns; hence, to doze in public, as used in this structure, is an adjective phrase.

Correspondingly, the grammatical name of to doze in public is infinitive phrase as an adjective phrase (or simply, adjective phrase), and the grammatical function is that it is modifying the noun Opens in new window, tendency.

Again, survey another example below.

  • √  She deceived the authority to travel abroad.

We understand that the infinitive phrase, to travel abroad, immediately follows the noun, authority. This implies that to travel abroad is modifying the noun, authority. And we know that only adjectives modify nouns; hence, to travel abroad, as used in this structure, is an adjective phrase.

For that reason, the grammatical name of to travel abroad is infinitive phrase as an adjective phrase (or simply, adjective phrase), and the grammatical function is that it is modifying the noun, authority.

Finally, all the infinitive phrases in the sentences below are adjective phrases because they immediately come after their respective nouns; for instance, they are modifying their respective nouns. The noun they modify is shown in parentheses.

  • He took the money to save at the bank.
    → (modifies the noun money)
  • He has a woman to marry this year.
    → (modifies the noun woman)
  • They advised their daughter to teach mathematics in school.
    → (modifies the noun daughter)
  • I used my savings to travel every month.
    → (modifies the noun savings)

3.  Infinitive Phrases used as Adverb Phrases

An infinitive phrase is considered an adverb phrase only if it immediately follows a predicate adjective. And we know that a predicate adjective Opens in new window is an adjective Opens in new window that immediately follows a linking verb Opens in new window.

For example, ponder the sentences below.

  • √  He was eager to rest for a while.

We believe that the adjective, eager, is a predicate adjective Opens in new window since it immediately follows the linking verb Opens in new window, was. More to the point, we see that the infinitive phrase, to rest for a while, immediately follows eager (which is a predicate adjective).

This implies that to rest for a while is modifying the adjective, eager. And we know that only adverb can modify adjective; hence, to rest for a while is an infinitive phrase as an adverb phrase.

Consequently, the grammatical name of to rest for a while is infinitive phrase as an adverb phrase, (or simply, an adverb phrase) and the grammatical function is that it is modifying the adjective, eager.

Finally, let's ponder the sentence below.

  • √  It is interesting to hear nice stories.

We believe that the adjective, interesting, is a predicate adjective since it immediately follows the linking verb is. Above and beyond, we see that the infinitive phrase, to hear nice stories, immediately follows interesting (which is a predicate adjective).

This implies that to hear nice stories is modifying the adjective, interesting. And we know that only adverb can modify adjective Opens in new window; hence, to hear nice stories is an infinitive phrase as an adverb phrase.

As a result, the grammatical name of to hear nice stories is infinitive phrase as an adverb phrase, (or simply, an adverb phrase) and the grammatical function is that it is modifying the adjective, interesting.