helping verb

What is an auxiliary verb?

An auxiliary verb, also called a helping verb, is a verb that is used with another verb (or two other verbs) in a verb phrase.

The auxiliary verbs (which include be, have, do, and the modal verbs like may, shall, will, can, and must) combine with verbs to do things like show a verb's tense or form a question.

Be, have, and do are used as both independent verbs and as auxiliary verbs.

Have is used to form all the perfect tenses, the tenses that are used to refer to an action or state that is completed at the time of speaking or at a time spoken of:

I have packed the car. (present perfect)

I had packed my suitcase the night before. (past perfect)

I will have packed everything by the time you arrive. (future perfect)

I will have been traveling for three weeks by the time I return. (future perfect progressive)

Be is used to form all the progressive tenses, the tenses that are used to refer to an action or state that is continuing to happen:

I am leaving soon. (present progressive)

I was making a few calls first. (imperfect tense, also called past progressive)

I will be driving across much of the country. (future progressive)

I will have been traveling for three weeks by the time I return. (future perfect progressive)

Be is also used in the passive voice, and to join infinitives plus to to the subject of a sentence or clause:

My route was recommended by a friend. (passive voice)

I am to arrive before nightfall.

Do occurs as an auxiliary verb mainly in negative sentences and in questions:

I do not have a map.

Do you have a map handy?

Do is also occasionally used for emphasis. In this use, do is followed by an infinitive without to:

I do think I'll be able to find my way without a problem.

Do may also substitute for another verb that has just been stated:

My dog enjoyed the drive immensely, and so did I.

A small group of auxiliary verbs, called the modal verbs (or modal auxiliary verbs, modal auxiliaries, or simply modals) are only used in combination with ordinary verbs. A modal verb changes the other verb's meaning to something different from simple fact. Modals may express permission, ability, prediction, possibility, or necessity.

The principal modal verbs are: can, could, may, might, must, ought, shall, should, will, and would.

The modal verbs are different from ordinary verbs in several ways:

1) They have no inflections at all; that is, they lack an -ing form, an -ed form, and even an -s form for the third-person singular.

2) A modal verb is always followed by the infinitive form of a verb (unless that verb has already been stated) but never follows another verb.

3) Modal verbs do not follow to and are not followed by to. (Ought to, like the near-modal verb have to, is a special case.)

In their simple form, modal verbs normally refer to present or future time:

I must be nearly there by now.

I might arrive a bit later than I'd anticipated.

A trip like this can take many hours more than one expects.