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Concourse 2

Primary Auxiliary verbs




An auxiliary verb is one which cannot usually stand alone and retain a clear meaning.  Compare, for example,

  1. He can
  2. He went
  3. They are
  4. She smokes

It's clear that the meanings of sentences 1. and 3. are obscure unless we have some more information.  We need to know what He can do and What they are or are doing.
Sentences 2. and 4., however, are complete in themselves and need no further elaboration.
The verbs can and are in these examples are auxiliary verbs and the verbs went and smokes are main or lexical verbs.  This is a crucial distinction.


Complication 1

Some verbs can function in both ways.  They can be auxiliaries and they can also be lexical or main verbs.  For example, in these sentences the verbs can, be and have are functioning in both ways.  Can you identify which is which?
Click here when you have an answer.

  1. The factory cans tomatoes
  2. She can tell you tomorrow
  3. She is a teacher
  4. She is arriving now
  5. She has the papers
  6. She has been to the USA

Here, we are only concerned with verbs acting as auxiliaries.


Complication 2

There are two kinds of auxiliary verbs in English: Primary Auxiliaries and Modal Auxiliaries.
Modal Auxiliary verbs include, for example, can, may, might, should, ought to etc.  These verbs express notions such as possibility, permission, obligation, likelihood and so on.  There are guides to these elsewhere on the site.  The place to start is the guide to modality, linked in the list of related guides at the end.
The ones in focus here are the primary auxiliaries and for our purposes, these are be, have, do and get.


Complication 3

Some auxiliaries (notable will) are usually called modal but often act to give grammatical information by forming a tense with a main verb.  For this reason, some people will classify will and would as Primary Auxiliaries.  That is a sensible approach because both verbs can act in both ways.  The classification is then split so when they act as primary modal auxiliaries, that is what they should be called and likewise when they act as modal auxiliary verbs.
If you want to learn more about the functions of will and would, go to the guide to modality.


What do the Primary Auxiliary verbs actually do?

Auxiliary verbs in general are sometimes called 'helping verbs' and, although that is rather babyish, there is a kernel of truth in it.  Primary Auxiliaries help in the sense that they provide grammatical information and tell us how to view the lexical or main verb which follows.
We'll take them one by one.


The first thing to note about this verb is that it is very frequently seen as a lexical or main verb in things such as: He did the work carefully, She is doing her homework, They do that a lot etc.  The lexical verb does not concern us here.

The second thing to note is that this verb only functions as a Primary Auxiliary in present simple and past simple tenses.  Nowhere else.  For this reason, it is often referred to as an operator because it can operate on a main verb in, for example:
    He does enjoy music
in which the verb takes on the ending (es) which would normally occur on the lexical or main verb (enjoys).

do as a Primary Auxiliary verb

What function is the verb do performing in these examples?

  1. Did you see the film?
  2. I don't understand
  3. I do demand it
  4. Don't talk to me

Click here when you have an answer.

The summary of do:


In questions, imperatives and negatives, the verb is not usually stressed.  The stress in these cases is on the lexical or main verb because that is carrying the meaning.  In emphasising uses, however, the verb is stressed.


The first thing to note is that have can function as a lexical or main verb and frequently does.  For example:

The second thing to note is that when it is a lexical or main verb, we can:

The third thing to note is that when the verb is a Primary Auxiliary, we never use the do auxiliary with it.  Never.  It is not possible to say something like
    *Do you have met him?
and that is a cause for error at lower levels especially.

The fourth complication is that have when it is followed by to + an infinitive is a modal auxiliary verb akin to must as in, e.g.
    I have to leave now
and in this case it does not qualify as a primary auxiliary verb but is a modal auxiliary verb.

have as a Primary Auxiliary verb

What function is the verb have performing in these examples?

  1. Have you seen the film?
  2. I won't have done it by then
  3. I haven't eaten this before
  4. He has spent all his money
  5. He had already left when I arrived
  6. I hadn't expected something so beautiful, had you?
  7. I had my tooth taken out
  8. I'll have the window repaired

Click here when you have an answer.

The summary of have:



The first thing to note is that the verb be can function as a lexical or main verb and usually expresses:

  1. The relationship between two things in, for example, She is a teacher, It is a mistake
  2. The characteristics of something in, e.g., They are French, He is very clever

In these cases it is known as a copular verb and joins two things together.  For more, see the guide to copular verbs.

The second thing to notice is that this verb has eight different forms (most have only four or five): be (the base form), am, is, are (present forms), was, were (past forms), being (the present participle and gerund) and been (the past participle, often of the verb go).  All of these can be used when the verb is acting as a lexical or main verb or as an auxiliary.  That is confusing for learners at lower levels.  Here is this very irregular verb compared to a regular lexical or main verb, smoke, so you can see the complications:

To show: be smoke
Infinitive be smoke
First person singular (I) am
Second person (you) are
Third person plural (they)
First person plural (we)
Third person singular (he, she, it) is smokes
Present participle / gerund being smoking
Past participle been smoked
First person singular (past) was
Second person (past)
First person plural (past) were
Third person plural (past)

be as a Primary auxiliary verb

What function is the verb be performing in these examples?

  1. I am seeing him tomorrow?
  2. They were playing tennis at the time
  3. She was explaining it to me
  4. The window was broken by a bird
  5. The car has been repaired

Click here when you have an answer.

The summary of be:

be summary 


This guide is slightly unusual in classifying get as a Primary Auxiliary but it can function this way as well as functioning as a lexical or main verb.
As a lexical verb it has a very wide range of meanings.  Some dictionaries will list over 40 different meanings of the verb ranging from achieve, reach, arrive etc. to become, grow and leave.  Adding particles to get such as on, out, over, to etc. adds even more meanings.
Here, however, we are interested in get as an auxiliary verb.

get as a Primary Auxiliary verb

What function is the verb be performing in these examples?

  1. I got the house painted
  2. She got her foot trapped
  3. The window got damaged
  4. They will get arrested for it

Click here when you have an answer.

So, in sentences a. and b., we can replace get with have and in sentences c. and d., we can replace it with be.
In both cases get is usually less formal.

The summary of get:



Here's the big picture:


Take a short test.

Related guides
modality essentials for a guide to the other sort of auxiliary verbs
PDF document for a list of primary and modal auxiliary verbs
modal auxiliary verbs one by one for a traditional guide to pure (or central) modal auxiliary verbs
semi-modal auxiliary verbs the more technical guide to semi- and marginal modal auxiliary verbs
tense and aspect to see how primary auxiliaries work to make tense and aspect forms
voice with a focus on the active and passive
copular verbs for a guide to how be and other verbs work to link the subject and complement
the present perfect for a guide to how have works to form the language's most troublesome and misunderstood tense
the causative a more technical guide to using have and get to make a form of the passive