Examples and Observations:
- "[A]uxiliaries are required with non-finite verbs. This is their role to mark non-finite verb forms for tense, aspect and voice, which non-finite verbs cannot express. Finite verbs mark these features on their own."
(Bernard T. O'Dwyer, Modern English Structures: Form, Function, and Position. Broadview Press, 2000)
- "[S]entences that include a non-finite Verb Group are (58) and (59), with the non-finite Verb Groups in bold. . . .
(58) Seeing the ordinary as extraordinary is something we all like to do.In (58), seeing, is, like, and do are lexical verbs, but only is and like are finite. In (59), forgot and google are the lexical verbs, but only forgot is finite."
(59) She forgot to google them.
(Elly van Gelderen, An Introduction to the Grammar of English, rev. ed. John Benjamins, 2010)
- "A non-finite verb differs from a finite verb in that it cannot (normally) be used as the main verb of a clause. Typically, the non-finite verb lacks agreeement for person, number, and gender with its first argument or Subject, is unmarked or reduced with respect to distinctions of Tense, Aspect, and Mood, and has certain properties in common with adjectival or nominal predicates."
(Simon C. Dik and Kees Hengeveld, The Theory of Functional Grammar. Walter de Gruyter, 1997)
- "There are three types of nonfinite verb-forms in English: viz. (i) uninflected infinitive forms which comprise simply the base or stem of the verb with no added inflection (such forms are frequently used after the so-called infinitive-particle to; (ii) gerund forms which comprise the base plus the -ing suffix; (iii) and (perfect/passive) participle forms which generally comprise the base plus the -(e)n inflection (though there are numerous irregular participle forms in English). Thus, the bracketed clauses in (4) below are all nonfinite, because they contain only nonfinite verb-forms: for example the italicised verb in (4)(a) is an infinitive, that in (4)(b) is a gerund, and that in (4)(c) is a (passive) participle:
(4) (a) I've never known [John (to) be so rude to anyone]
(4) (b) We don't want [it raining on your birthday]
(4) (c) I had [my car stolen from the car-park]"
(Andrew Radford, Transformational Grammar: A First Course. Cambridge Univ. Press, 1988)