209. A verb is a word which can assert something (usually an action) concerning a person, place, or thing ([§ 14]).

Most verbs express action. Some, however, merely express state or condition. Thus,—

A verb-phrase is a group of words that is used as a verb ([§ 15]).

210. Certain verbs, when used to make verb-phrases, are called auxiliary (that is, “aiding”) verbs, because they help other verbs to express action or state of some particular kind ([§ 16]).

The auxiliary verbs are is (are, was, were, etc.), may, can, must, might, shall, will, could, would, should, have, had, do, did.

The auxiliary verb may be separated from the rest of the verb-phrase by other words.