The document summarizes different uses of infinitives in sentences. It discusses how infinitives: 1) Are the base form of a verb preceded by "to" and name an action without a subject. 2) Can function as nouns, adverbs, or adjectives in a sentence. 3) Can act as subjects, direct objects, or predicate nominatives when used as nouns. 4) Must modify verbs, adjectives, or other adverbs when used as adverbs. 5) Modify nouns or pronouns when used as adjectives.