toinfinitives

The to-infinitive is the non-finite form of a verb formed with the particle to plus the base verb, as in to go or to eat. It contrasts with the bare infinitive, which occurs without to in certain constructions (let him go, must eat). The to-infinitive also has aspectual variants: the simple to-infinitive (to go), the perfect infinitive (to have gone), and the progressive infinitive (to be going).

Functions of the to-infinitive include acting as the subject of a sentence (To learn a language takes time), serving as the direct object after verbs such as want, decide, or need (I want to travel), and functioning as a complement after linking verbs (Her goal is to study). It can express purpose, especially with verbs of motion or intention: I came here to study; in more formal writing, in order to is used to emphasize purpose. The to-infinitive also modifies adjectives and nouns (It is easy to read; the plan to expand).

Usage with verbs involves choosing between a to-infinitive and a gerund after many verbs. Some verbs are followed by a to-infinitive (decide to go, hope to visit, plan to return), while others prefer a gerund (enjoy reading, avoid touching). Some verbs change meaning depending on the form: stop to eat (pause to eat) vs stop eating (cease eating); remember to do vs remember doing; forget to do vs forget doing. The to-infinitive can also express results or expectations with perfect forms (to have finished) and is used after certain patterns such as be going to and may appear with modal verbs in complex tenses.

Style notes include that split infinitives (to boldly go) are common and generally accepted in modern English. The to-infinitive is a versatile tool for expressing purpose, intention, perception, and sequencing within sentences.