24강 / Concept 024 / to부정사의 형용사적 용법

Adjectival Use of the To-Infinitive

Teacher Lee Jeong-woo explains how a to-infinitive—to + base-form verb—can function as a noun, adjective, or adverb, focusing on its adjectival use.

Review: Noun Use

A to-infinitive can function as a noun in several roles: as a subject, subject complement, or object. In its adjectival use, by contrast, the infinitive modifies a noun.

How to Identify Adjectival Use

Use both structure and meaning to identify an adjectival to-infinitive:

1. Look for a noun before the to-infinitive. The infinitive may describe that noun.
2. Check whether the meaning fits. The phrase should convey an idea like “a noun to do something with or for.” A preceding noun alone does not prove that the infinitive is adjectival.

Examples:

• friends to help me — friends who can help me
• a book to read — a book that someone can read
• things to do — things that need to be done
• nothing to eat — no food available to eat

Why the Infinitive Follows the Noun

In English, longer modifiers commonly follow the nouns they describe. Because a to-infinitive is a multiword phrase, it typically comes after the noun. Participles and relative clauses can also follow the nouns they modify.

When to Use a Preposition

When the infinitive’s verb is intransitive in the relevant meaning, a preposition may be needed after the verb to connect it to the noun:

• a pen to write with
• paper to write on
• a chair to sit on
• a house to live in
• a friend to talk to/with

When the verb is transitive and takes the noun directly as its object, no additional preposition is needed:

• a book to read
• food to eat
• things to do

A transitive verb takes an object; an intransitive verb does not. Asking whether “something” naturally follows the verb can be a helpful starting point, though this shortcut is not always reliable.

Distinguishing Other Uses of “To”

In I went to the market to buy fruit, to buy fruit expresses purpose (“in order to buy fruit”), so it is adverbial. It does not modify market.

The word to also has different grammatical roles in these examples:

• In to the market, to is a preposition because it is followed by a noun.
• In to buy, to introduces an infinitive because it is followed by a base-form verb.

Suggested Study Approach

• Check both structure and meaning before labeling a to-infinitive.
• When a noun is followed by an infinitive, ask whether the phrase naturally means “a noun to do something.”
• Check whether the infinitive’s verb needs a preposition.
• Learn common combinations as chunks—such as write with, write on, sit on, and live in—rather than memorizing isolated translations.

The lesson concludes with practice questions on distinguishing noun, adjective, and other infinitive uses, as well as supplying missing prepositions.

Speakers and Sources

• Teacher Lee Jeong-woo — instructor and speaker throughout the lesson
• 중학영어TV — channel publishing the lesson