Infinitives

Infinitives are non-finite verb forms that do not show person, number, or explicit tense. In English, the most common form is the to-infinitive, created by to followed by the base form of the verb, as in to eat, to see, to become. A bare infinitive omits to and occurs after certain verbs and constructions, most notably after modal auxiliaries (can, may, must, shall, will) and after verbs of perception or causation such as see, hear, let, make, and help.

Infinitives can function in several ways. They may serve as the subject or the object of a sentence (To learn is to grow; She wants to travel). They can complete a verb (He decided to stay) or follow an adjective (It is easy to use). They can express purpose, as in He opened the door to let in fresh air, or appear in phrases such as in order to.

Infinitive phrases may include objects or modifiers: to finish the project on time, to read quickly but thoroughly. English also uses perfect and progressive infinitives to place the action relative to another event, such as to have eaten, to be reading, or to have been seen. The future-like going to construction is often discussed separately but is historically linked to the infinitive form of go.

Split infinitives, where an adverb separates to from the verb, such as to boldly go, have been debated. In modern usage they are generally accepted when they aid clarity or emphasis. Infinitives, as non-finite forms, do not indicate tense and can be negated (not to talk) or combined with auxiliary elements as needed.