Editing English language (section)

==== Auxiliary verb constructions ====
{{Main|Do-support|Subject–auxiliary inversion}}

English syntax relies on auxiliary verbs for many functions including the expression of tense, aspect, and mood. Auxiliary verbs form main clauses, and the main verbs function as heads of a subordinate clause of the auxiliary verb. For example, in the sentence ''the dog did not find its bone'', the clause ''find its bone'' is the complement of the negated verb ''did not''. [[Subject–auxiliary inversion]] is used in many constructions, including focus, negation, and interrogative constructions.

The verb ''do'' can be used as an auxiliary even in simple declarative sentences, where it usually serves to add emphasis, as in "I ''did'' shut the fridge." However, in the negated and inverted clauses referred to above, it is used because the rules of English [[syntax]] permit these constructions only when an auxiliary is present. [[Modern English]] does not allow the addition of the negating adverb ''not'' to an ordinary [[finite verb|finite]] lexical verb, as in ''*I know not''—it can only be added to an auxiliary (or [[copular verb|copular]]) verb, hence if there is no other auxiliary present when negation is required, the auxiliary ''do'' is used, to produce a form like ''I do not (don't) know.'' The same applies in clauses requiring inversion, including most questions—inversion must involve the subject and an auxiliary verb, so it is not possible to say ''*Know you him?''; grammatical rules require ''Do you know him?''{{sfn|Huddleston|Pullum|2002|page=114}}

Negation is done with the adverb ''not'', which precedes the main verb and follows an auxiliary verb. A contracted form of not ''-n't'' can be used as an enclitic attaching to auxiliary verbs and to the copula verb ''to be''. Just as with questions, many negative constructions require the negation to occur with do-support, thus in Modern English ''I don't know him'' is the correct answer to the question ''Do you know him?'', but not ''*I know him not'', although this construction may be found in older English.{{sfn|Huddleston|Pullum|2002|pages=786–790}}

Passive constructions also use auxiliary verbs. A passive construction rephrases an active construction in such a way that the object of the active phrase becomes the subject of the passive phrase, and the subject of the active phrase is either omitted or demoted to a role as an oblique argument introduced in a prepositional phrase. They are formed by using the past participle either with the auxiliary verb ''to be'' or ''to get'', although not all varieties of English allow the use of passives with ''get''. For example, putting the sentence ''she sees him'' into the passive becomes ''he is seen (by her)'', or ''he gets seen (by her)''.{{sfn|Miller|2002|pages=26–27}}