Chapter 5-5-3: Infinitives
Infinitives are verbals formed by placing "to" in front of the base form (the "simple present form") of a verb. For example, "to dance, to eat, to forget."
FORM: ["to"] + [base form of the verb]
Infinitives can act as adjectives, adverbs, or nouns. For example:
To play is fun. [Noun; subject of the verb is. To prove that it's a noun, we can change the infinitive to a gerund: Playing is fun.]
I love to eat. [Noun; direct object of the verb love. To prove that it's a noun, change the infinitive to a gerund: I love eating.]
✔ TIP: when a main verb (the verb that comes right after the subject) has an object that is a noun or a pronoun, it is usually followed by an infinitive and not a gerund.
I had a car to offer. [Adjective modifying car. The fact that it's modifying a noun makes it an adjective. To prove this, turn it into an adjective clause: I had a car that I offered.]
✔ TIP: infinitives are usually used after an adjective. A gerund is sometimes possible, but usually an infinitive is better.
Dave walked to meet her. [Adverb modifying the verb meet. To prove it this time, turn it into an adverbial clause: Dave walked so he could meet her.]
✔ TIP: unfortunately, there are times when either a gerund or an infinitive can follow the main verb in a sentence. There are no rules in this case and second language learners must memorize the most common verbs that take an infinitive.
English as a second language learners encounter a great deal of difficulty distinguishing between when to use "gerunds" versus "infinitives." You are advised to read Chapter 5-5-2 on gerunds.You should also check out Chapter 5-5-4 to learn about exceptions and problems associated with verbals.