In
English grammar, certain verb forms are classified as
auxiliary verbs. Exact definitions of this term vary; an auxiliary verb is generally conceived as one with little semantic meaning of its own, which modifies the meaning of another verb with which it co-occurs. In English, verbs are often classed as auxiliaries on the basis of certain grammatical properties, particularly as regards their
syntax – primarily whether they participate in
subject–auxiliary inversion, and can be
negated by the simple addition of
not after them.