Learn on PengiElements of Language, 5th CourseChapter 3: The Phrase: Kinds and Functions

Lesson 4: The Infinitive and the Infinitive Phrase

In this Grade 8 grammar lesson from Elements of Language, 5th Course, students learn to identify and use infinitives and infinitive phrases, understanding how these verb forms function as nouns, adjectives, or adverbs in a sentence. The lesson also covers the distinction between the word to as a preposition versus as the sign of an infinitive, and introduces the concept of split infinitives in formal writing. Practice exercises guide students through recognizing infinitive phrases, locating the infinitive within them, and correcting improperly split infinitives.

Section 1

The Infinitive

Definition

An infinitive is a verb form that can be used as a noun, an adjective, or an adverb. Most infinitives begin with to.

Explanation

Wondering if to is part of an infinitive or a preposition? It's simple! If 'to' is followed by a verb, like 'to run' or 'to dream', it's an infinitive. If it's followed by a noun or pronoun, like 'to the store' or 'to her', it's a preposition.

Examples

  • NOUN: My cat loves to sleep. [The infinitive to sleep is a noun, the direct object of the verb loves.]
  • ADVERB: The audience waited patiently to applaud. [The infinitive to applaud is an adverb modifying the verb waited.]
  • ADJECTIVE: His decision to travel was a surprise. [The infinitive to travel is an adjective describing the noun decision.]

Section 2

The Infinitive Phrase

Definition

An infinitive phrase consists of an infinitive and any modifiers or complements the infinitive has. The entire phrase can be used as a noun, an adjective, or an adverb.

Explanation

Think of an infinitive phrase as an infinitive's 'entourage.' It includes the infinitive (like 'to go') plus any objects, adverbs, or phrases that complete its meaning. This whole group then acts as a single part of speech—either a noun, adjective, or adverb—making your sentences more detailed.

Examples

  • NOUN: Sarah plans to visit her cousins this weekend. [The infinitive phrase acts as the sentence's direct object.]
  • ADJECTIVE: Her desire to win the championship fueled her training. [The infinitive phrase modifies the noun desire.]
  • ADVERB: To get a better grade on the test, you should study every night. [The infinitive phrase modifies the verb should study.]

Section 3

Split Infinitives

Definition

An infinitive is split when a modifying word or words come between the sign of the infinitive, to, and the verb form.

Explanation

While you might hear split infinitives in everyday conversation, it's best to avoid them in formal essays and reports. The rule is about clarity and style. Keeping the 'to' and its verb partner together makes your writing sound more polished and professional. Simply move the modifier before or after the infinitive.

Examples

  • SPLIT INFINITIVE: She decided to quickly run to the store before it closed. [The adverb quickly splits the infinitive to run.]
  • WHOLE INFINITIVE: She decided to run quickly to the store before it closed. [The parts of the infinitive are no longer separated.]
  • SPLIT INFINITIVE: The goal is to always do your best.
  • WHOLE INFINITIVE: The goal is always to do your best. [The adverb always is moved so it does not split to do.]

Book overview

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Chapter 3: The Phrase: Kinds and Functions

  1. Lesson 1

    Lesson 1: The Prepositional Phrase

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  2. Lesson 2

    Lesson 2: The Participle and the Participial Phrase

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  3. Lesson 3

    Lesson 3: The Gerund and the Gerund Phrase

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  4. Lesson 4Current

    Lesson 4: The Infinitive and the Infinitive Phrase

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  5. Lesson 5

    Lesson 5: The Appositive and the Appositive Phrase

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Lesson overview

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Section 1

The Infinitive

Definition

An infinitive is a verb form that can be used as a noun, an adjective, or an adverb. Most infinitives begin with to.

Explanation

Wondering if to is part of an infinitive or a preposition? It's simple! If 'to' is followed by a verb, like 'to run' or 'to dream', it's an infinitive. If it's followed by a noun or pronoun, like 'to the store' or 'to her', it's a preposition.

Examples

  • NOUN: My cat loves to sleep. [The infinitive to sleep is a noun, the direct object of the verb loves.]
  • ADVERB: The audience waited patiently to applaud. [The infinitive to applaud is an adverb modifying the verb waited.]
  • ADJECTIVE: His decision to travel was a surprise. [The infinitive to travel is an adjective describing the noun decision.]

Section 2

The Infinitive Phrase

Definition

An infinitive phrase consists of an infinitive and any modifiers or complements the infinitive has. The entire phrase can be used as a noun, an adjective, or an adverb.

Explanation

Think of an infinitive phrase as an infinitive's 'entourage.' It includes the infinitive (like 'to go') plus any objects, adverbs, or phrases that complete its meaning. This whole group then acts as a single part of speech—either a noun, adjective, or adverb—making your sentences more detailed.

Examples

  • NOUN: Sarah plans to visit her cousins this weekend. [The infinitive phrase acts as the sentence's direct object.]
  • ADJECTIVE: Her desire to win the championship fueled her training. [The infinitive phrase modifies the noun desire.]
  • ADVERB: To get a better grade on the test, you should study every night. [The infinitive phrase modifies the verb should study.]

Section 3

Split Infinitives

Definition

An infinitive is split when a modifying word or words come between the sign of the infinitive, to, and the verb form.

Explanation

While you might hear split infinitives in everyday conversation, it's best to avoid them in formal essays and reports. The rule is about clarity and style. Keeping the 'to' and its verb partner together makes your writing sound more polished and professional. Simply move the modifier before or after the infinitive.

Examples

  • SPLIT INFINITIVE: She decided to quickly run to the store before it closed. [The adverb quickly splits the infinitive to run.]
  • WHOLE INFINITIVE: She decided to run quickly to the store before it closed. [The parts of the infinitive are no longer separated.]
  • SPLIT INFINITIVE: The goal is to always do your best.
  • WHOLE INFINITIVE: The goal is always to do your best. [The adverb always is moved so it does not split to do.]

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 3: The Phrase: Kinds and Functions

  1. Lesson 1

    Lesson 1: The Prepositional Phrase

    LearnPractice
  2. Lesson 2

    Lesson 2: The Participle and the Participial Phrase

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  3. Lesson 3

    Lesson 3: The Gerund and the Gerund Phrase

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  4. Lesson 4Current

    Lesson 4: The Infinitive and the Infinitive Phrase

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  5. Lesson 5

    Lesson 5: The Appositive and the Appositive Phrase

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