Auxiliary Verbs (be, do, have)

Auxiliary verbs (also called helping verbs) are be, do, and have. They cannot stand alone as main verbs, but they “help” other verbs by forming different tenses, questions, negatives, and more.

Be: Used to form continuous tenses (am/are/is + ...ing) and passive voice.
Do: Used to form questions and negatives in the present and past simple, and for emphasis.
Have: Used to form perfect tenses (have/has/had + past participle).

Be

Use be to form:

Continuous (progressive) tenses: am/is/are + verb -ing
Passive voice: am/is/are/was/were + past participle
Some simple verb forms (e.g., I am, You are)

Be changes form depending on subject and tense:

Subject	Present	Past
I	am	was
You	are	were
He/She/It	is	was
We/You/They	are	were

Be Conjugation Chart

Tense	Singular (I/He)	Plural (We/They)
Present	I am / He is	We/They are
Past	I was / He was	We/They were
Future	I will be	We will be
Present Perf.	I have been	We have been
Past Perf.	I had been	We had been

Be Examples

Type	Example
Continuous Tense	She is studying English.
Passive Voice	The book was written by Tom.
Simple Form	I am a teacher.

Use do mainly for:

Making questions and negatives in simple present and past
Adding emphasis (“I do want to go!”)

Do changes form for subject and tense:

Subject	Present	Past
I/You/We/They	do	did
He/She/It	does	did

Do Conjugation Chart (for helping)

Form	Singular (He)	Plural (They)
Present Affirmative	He does	They do
Past Affirmative	He did	They did
Present Question	Does he...?	Do they...?
Past Question	Did he...?	Did they...?

Choose the correct past simple auxiliary for making questions about a plural subject.

Have

Did

Does

Did

'Did' is used for all subjects to form past simple questions.

Do Examples

Use	Example
Simple Affirmative	I do my homework.
Simple Negative	She doesn’t like fish.
Question	Do you play tennis?
Past Question	Did they arrive on time?
Emphasis	I do want to see it!

Use have to form perfect tenses:

Present perfect: have/has + past participle
Past perfect: had + past participle
Perfect continuous: have/has/had + been + verb -ing

Have changes for person and tense:

Person	Present	Past
I/You/We/They	have	had
He/She/It	has	had

Have Conjugation Chart (as auxiliary)

Tense	Singular (He)	Plural (They)
Present Perf.	He has eaten	They have eaten
Past Perf.	He had eaten	They had eaten
Present Perf. Cont.	He has been eating	They have been eating
Past Perf. Cont.	He had been eating	They had been eating

Which form completes this sentence correctly? 'He ___ eaten already.'

did

has

have

had

has

'He' requires 'has' in the present perfect tense.

Have Examples

Tense	Example
Present Perfect	I have finished my work.
Past Perfect	They had left before me.
Present Perf. Cont.	She has been running for 10 minutes.
Past Perf. Cont.	We had been waiting for an hour.

Summary

Be: am/is/are/was/were — continuous & passive
Do: do/does/did — questions, negatives, emphasis (simple)
Have: have/has/had — perfect and perfect continuous

Bonus: Common Mistakes

Be + verb (-ing): “She is go to school” → *She is going to school.
Do in questions: “You do like ice cream?” → *Do you like ice cream?
Have + past participle: “I have wrote the letter” → *I have written the letter.
Using auxiliary without main verb: “She does” → She does ? (Add main verb: She does work.*)
Mixing tenses: “He has ate” → *He has eaten.

Practice

Be: Write 2 sentences using “is” and “was.”
Do: Make 1 question and 1 negative using “do/does” and “did.”
Have: Write 2 sentences, one in present perfect and one in past perfect.

English

Be