Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
AUXILIARIES, AUXILIARY VERBS
These are the parts of speech sometimes called helping verbs. They are a finite list of words (we rarely create new ones) that English uses with certain forms of verbs to help form tenses, moods, voices, and aspects of those verbs. The chief auxiliaries are shall, will, should, would, may, might, can, could, ought, have, had, be, and do. Some, such as have, be, and do, come in various forms; others, like ought, are monoforms. Many grammars assert that auxiliaries are not verbs at all, since they behave differently from verbs: most of them have no past participles such as verbs have. See BE; CAN (1); COULD; DO (1); HAD; HAVE; MAY; OUGHT; SHALL; SHOULD.
