Go to this verbs and their essential functions for understanding the content of sentences.

Here is a list of helping or auxiliary verbs: can, could, would, should, do, does, did, has, have, had, may, might, must, shall, and will plus the eight forms of the verb to be (am, are, be, been, being, is, was, were).

The auxiliary verbs are those which can't stand by themselves, but are always in combination with a "full verb"; for example, it is not acceptable to say, "We can home", but "We can go home." "Can" being the auxiliary verb and "go" being the full verb.

"Have" can act as both an auxiliary verb in the forms of the present perfect, past perfect, present perfect progressive, and past perfect progressive forms; as indicated by the following examples:

"I have gone to the store." (present perfect)

"She had already set the table before the guests came." (past perfect)

"She has been washing the car for the last two hours." (present perfect progressive)

"She had been washing the dishes before the phone rang." (past perfect progressive)

The verb "have" can stand alone as a full verb, too: "I have a basket of apples."

The verb "do" is about the same as "have". It can be used as a full verb or as an auxiliary verb:

"Jim's wife did the shopping today."

"The bus did stop and it did pick up the waiting passengers on time."