Verbs which have the past or the present form are called finite verbs. Verbs in any other form (infinitive, ing, or ed) are called nonfinite verbs. This means that verbs with tense are finite, and verbs without tense are nonfinite. The distinction between finite and nonfinite verbs is a very important one in grammar, since it affects how verbs behave in sentences.
Nonfinite verbs found in English typically are infinitives, participles and gerunds; unlike finite verbs, they cannot serve as the root of an independent clause. They sometimes are called verbals—although that term has traditionally applied only to participles and gerunds. Similar nonfinite forms found in some other languages include converbs, gerundives and supines.
Nonfinite verbs typically are not inflected by grammatical tense and they present little inflection for other grammatical categories as well. Generally, they also lack a subject dependent. One or more nonfinite verbs may be associated with a finite verb in a finite clause, composing the elements of a verb catena, or verb chain.
Because English to a large extent lacks inflectional morphology, the finite and nonfinite forms of a verb may appear the same in a given context. In such a case, the environment surrounding the verb must be examined to determine whether it is finite or nonfinite.
- non-finite forms possess the categories of voice, perfect and aspect;
- non-finites are not restricted in number and person by any grammatical subject;
- they combine the characteristics of a verb with those of some other part of speech;
- verbals cannot form a predicate by themselves but they can function as part of a compound verbal predicate: She suddenly began to speak; They were caught stealing the jewellery.
All non-finites may be part of the so-called predicative constructions: I didn’t expect you to come; He found her crying bitterly; I had the piano tuned.