Grammar: Word classes: Verbs: Verb formation

Auxiliary verbs (be, have, do)

What are auxiliary verbs?

Auxiliary verbs are 'helping verbs':

The main auxiliary verbs (be, do, have) provide us with important information about the action or event, they allow us to interact with each other, and they allow us to organise information in different ways in the clause.

Providing information about the action or event, ie the time an action or event took place (tense):

When did she arrive? [past time indicated]
        past simple

How the action or event should be viewed, eg is the event in progress at the time of speaking? (aspect):

Bozo is watching TV. [event in progress]
    present continuous

Interacting with each other. Auxiliary verbs are a very important aspect of the grammar when we want to make Statements and ask Questions (mood):

He        has            eaten his dinner. [Statement]
         auxiliary

Has            he        eaten his dinner yet? [Question]
auxiliary

Organising information in different ways - they allow us to form active and passive voice clauses (voice):

Someone broke the window last night. [active voice]

The window was broken last night. [passive voice]
                auxiliary

For more information, see:

	Grammar: Groups & phrases: Verb group: Time & tense: Overview
	Grammar: Clause: Using clauses to interact: Overview
	Grammar: Groups & phrases: Verb group: Structure of the verb group: Voice: active and passive

There can be one or more auxiliary verbs which go before the lexical verb:

SleepStealer     had           been          working      hard all night.                           
                     auxiliary 1     auxiliary 2          lexical verb

In fact, it is possible to have many auxiliary verbs piled up together:

SleepStealer   worked      hard all night.     

SleepStealer   was working      hard all night.      

SleepStealer   had been working      hard all night.      

SleepStealer   is going to have been working      hard all night.     

The first verb in the verb group is the Finite auxiliary verb, which can be followed by one or more other auxiliary verbs:

Here are the Finite forms of the three main auxiliary verbs:

If the verb group is non-Finite, then there will be no Finite verb in the verb group. Consider the possibilities with the verb eat:

to eat [infinitive]
eating [present participle]
eaten [past participle]

A non-Finite verb group may also include auxiliary verbs. In such cases the choice will be of a non-Finite auxiliary verb:

to have eaten / to be eaten
having eaten / being eaten
to be going to eat / to be going to be eaten

When dealing with language in the classroom, it is useful to be able to identify the different forms of the auxiliary verbs.