Auxiliary Verbs "Be," "Do," "Have"

An auxiliary verb helps the main (full) verb and is also called a "helping verb." With auxiliary verbs, you can write sentences in different tenses, moods, or voices. Auxiliary verbs are: be, do, have, will, shall, would, should, can, could, may, might, must, ought, etc. 

  • I think I should study harder to master English.
  • am having a cup of coffee.
  • You have been practicing hard.
  • It was written by a petitioner.
  • You may choose what you like.


The verb forms of be, do, and have can be used either as a main (full) verb or an auxiliary verb. The following examples show these verbs used as auxiliary verbs. 

Be = am / is / are

Be can be used as an auxiliary verb or the main verb in a sentence.

It tells us that an action is happening now or is going to happen in the future.

Be is also used to make passives.

Are is used for they and we.

Was is used for the past tense of am and is.

Were is used for the past tense of you, we and they

1. "Be" as an auxiliary verb

a. Used in progressive sentences:

  • I am taking a bath.
  • She is preparing dinner for us.
  • They have been studying all night.


b. Used in passive sentences:

  • I was given a free meal.
  • He was seen by fans at the airport.
  • This song has been sung by all nations.


c. Used in  questions:

  • Am I in the right place?
  • Are you my new boss?
  • Are we nearly there?
  • Are they the best players on the team?
  • Is he/she old enough to go to bars?

d. Used in  negative sentences:

  • I am not. (I aren't)
  • You are not. (you aren't)
  • We are not. (we aren't)
  • They are not. (they aren't)
  • He/she is not. (he/she isn't)


2. "be" as a full verb

The verb be can also be a full verb. In this case, it's not followed by another verb. If be is used as a full verb, we do not need an auxiliary in negative sentences or questions.

  • Positive sentence: They are fifteen years old.
  • Negative sentence: They are not fifteen years old.
  • Question: Are they fifteen years old?


Do / does / did

Do is common for forming questions and making negatives.

Did is used for do and does in the past tense. Do and does is never used for the past.

a. In statements

  • I do my homework.
  • You do the laundry.
  • We do the washing up.
  • They do yoga.
  • He/she does the cleaning.

b. In questions

  • Do I know you?
  • Do you live here?
  • Do we have time?
  • Do they come from Vietnam?
  • Does he/she drive to work?

c. In negative sentences

  • I do not. (I don't)
  • You do not. (you don't)
  • We do not. (we don't)
  • They do not. (they don't)
  • He/she does not. (he/she doesn't)


Have = has / had

Have is used to make the present perfect tense (it is always followed by the past participle).

Has is used for the third person singular.

Had is used for past tenses especially the past perfect tense. It describes an action that began in the past and continues into the present or that occurred in the recent past.

a. In statements

  • I have a dog.
  • You have something on your shirt.
  • We have seen it before.
  • They have called me three times.
  • He/she has lived in America.

b. In negative sentences

  • I have not. (I haven't/ I've not)
  • You have not. (you haven't/you've not)
  • We have not. (we haven't/we've not)
  • They have not. (they haven't/they've not)
  • He/she has not (he/she hasn't)



Other common auxiliary verbs are:

can, could, may, might, must, ought, should, and would.

These are also known as modal verbs. We use them to show obligation, possibility and necessity.

For example:

  • Jack is late. He might be sleeping. (possibility)
  • I should clean my room today. (obligation)
  • I must wear a tie to school. (necessity)


Answering questions

Auxiliary verbs are useful in giving short answers to questions.

Basically, your answer can end with the auxiliary verb.

The following examples are natural and completely acceptable ways to answer questions:

Do you like reading?
Yes, I do (like reading)

Can you speak English?
Yes, I can (speak English)

Do you have a sister?
No, I don't (have a sister)