What Is an Auxiliary Verb? | Examples, Definition & List
Auxiliary verbs (aka helping verbs) are verbs used alongside the main verb to change its tense, mood, or voice.
For example, in “the book was written,” “written” is the main verb and “was” is an auxiliary verb helping to form the passive voice, indicating that the subject of the sentence is receiving the action.
Auxiliary verbs also help to form tenses, including the perfect tenses (e.g., “I have eaten already”), and the progressive tenses (e.g., “they are coming”).
He has lived here for a long time.
They were laughing loudly.
How are auxiliary verbs used in sentences?
Auxiliary verbs always appear with a main verb to change its tense, voice, or mood. The three main auxiliary verbs are “be,” “have,” and “do.”
Auxiliary verbs usually come before the main verb, though other words—such as adverbs—can come between the two. The auxiliary verbs need to be conjugated for tense and for subject-verb agreement.
Do you eat meat?
She has been waiting for hours.
Modal auxiliary verbs
Sometimes called just modal verbs, modal auxiliary verbs provide additional context regarding the possibility of something or a person’s control over something (e.g., giving permission or stating an obligation). Modal auxiliary verbs do not need to be conjugated for tense or subject-verb agreement. The same modal verbs can have different meanings depending on the context.
I can knit, but I can’t crochet. [ability]
It may be too late to go to the party. [possibility]
May I come in? [permission]
See the auxiliary verb list below for the full list of all modal verbs and their uses.
Phrasal modals precede the main verb and tend to have similar meanings to modal verbs.
We are going to start the movie soon.
We will start the movie soon.
You are supposed to wash your hands after using the toilet.
You should wash your hands after using the toilet.
Auxiliary verbs and tense
The auxiliary verbs “be” and “have” and the modal auxiliary “will” play an important role in forming tenses. The table below shows how to form each of the tenses with an example in the first person singular. Apart from “will,” these verbs all need to be conjugated for tense and subject-verb agreement.
| Past | Present | Future | |
|---|---|---|---|
| Simple | No auxiliary “I walked” |
No auxiliary “I walk” |
“Will” “I will walk” |
| Progressive (continuous) | “Be” (“was”, “were”) “I was walking” |
“Be” (“is,” “am,” “are”) “I am walking” |
“Will” + “be” “I will be walking” |
| Perfect | “Have” (“had”) “I had walked” |
“Have” (“have,” “has”) “I have walked” |
“Will” + “have” “I will have walked” |
| Perfect progressive (perfect continuous) | “Have” (“had”) + “be” (“been”) “I had been walking” |
“Have” (“have,” “has”) + “be” (“been”) “I have been walking” |
“Will” + “have” + “be” (“been”) “I will have been walking” |
Auxiliary verbs and mood
The grammatical mood of a verb or sentence indicates the attitude or intention of the speaker.
In some languages, verbs will take different and distinct forms to indicate different moods. In English, however, the same verb form can be used for different moods, and moods are often expressed through constructions rather than a specific form of the verb. These constructions can (but don’t always) include auxiliary verbs and modal verbs.
| Intention | Example | |
|---|---|---|
| Indicative | Make a factual or neutral statement | Jashan is working at the moment. |
| Ask a question (interrogative) | Do you want dessert?” | |
| State a condition (conditional) | I can cook dinner if you’re busy. | |
| Imperative | Make a demand or request | Don’t talk to me. |
| Subjunctive | Express a wish, demand, suggestion, doubt, or hypothetical scenario | I really do wish I could be there.” |
It is essential that you listen carefully.
You must listen carefully.
Some languages have other moods, such as the potential mood to indicate the probability of something, that are only expressed through modal auxiliary verbs in English.
Auxiliary verbs and the passive voice
To form the passive voice (where the subject is receiving instead of performing the action), use the auxiliary verb “be” before the past participle of the main verb.
The Taj Mahal is visited by 7 to 8 million people every year.
Other uses of auxiliary verbs
Auxiliary verbs can also be used in the following ways:
In negative statements
To make a negative statement, place the adverb “not” after the auxiliary verb (or after the first auxiliary verb if there’s more than one) and before the main verb.
I will not have been staying there long when you come to visit.
If the sentence doesn’t have an auxiliary verb, use a form of “do” and “not.” “Do” is conjugated for tense and subject-verb agreement instead of the main verb, so you will always use the main verb’s infinitive form.
I don’t understand trigonometry.
For emphasis
“Do” can be used alongside the main verb to emphasize it. It’s often used to contradict someone or to stress agreement with them. It can also be used to emphasize imperatives.
He does play the guitar very well.
I think you should accept the job.
I do think you should accept the job.
As question tags
We use question tags at the end of sentences to ask for confirmation about or seek agreement with a statement. If the main statement is positive, the tag should be negative, and vice versa.
The auxiliary verb in the question tag should match the auxiliary verb in the main statement. If the main statement doesn’t contain an auxiliary verb, use “do” (unless the main verb is “be,” in which case use a form of “be”).
She has a wonderful voice, doesn’t she?
You have been there, haven’t you?
You don’t like chocolate, do you?
In place of the main verb
If the main verb is already understood because it appeared earlier in the sentence or in the previous sentence, then auxiliary verbs can be used to avoid repetition.
This is common in sentences using the coordinating conjunction “but.” In this construction, if the first statement is negative, the second should be positive, and vice versa. If an auxiliary verb is used in the main statement, use the same type of auxiliary verb in the second statement. Otherwise, use “do” (unless the main verb is “be”).
I was watching the movie, but my brother wasn’t.
Karl took notes in the seminar, but Harry didn’t.
I am a teacher, but my husband isn’t.
Auxiliary verbs are also used in place of the main verb when answering questions.
A: I do.
Q: Have you been learning Spanish for a long time?
A: I have.
Auxiliary verb list
This list contains all the primary auxiliary verbs along with examples and information on how they are used.
| Auxiliary verb | Uses | Examples |
|---|---|---|
| Be (is, am, are, was, were, been) | Progressive tenses (the past progressive, present progressive, and future progressive) | I am thinking. |
| With “have”—perfect continuous tenses (past perfect continuous, present perfect continuous, and future perfect continuous) | She has been improving. | |
| Passive voice | The paper was graded. | |
| Do (does, did) | Interrogative sentences (questions) | Do you agree? |
| Negative sentences | He didn’t write the book | |
| Emphasis | I do like it. | |
| Have (has, had) | Perfect tenses (the past perfect, present perfect, and future perfect) | I have fed the goldfish. |
| With “be”—perfect progressive tenses (past perfect progressive, present perfect progressive, and future perfect progressive) | You have been reading for hours. |
We also have a list of modal auxiliary verbs along with their uses and examples.
| Modal verb | Uses | Examples |
|---|---|---|
| Can | Permission | Can you go now. |
| Request | Can you help me? | |
| Ability (present and future) | I can speak three languages. | |
| Possibility—something we believe is usually but not always true (present and future) | Algebra can be difficult to understand. | |
| May | Permission (formal) | You may speak. |
| Possibility—possible but uncertain or unknown | He may be there. | |
| Might | Permission/request (very formal) | Might I know who is calling? |
| Possibility—possible but uncertain or unknown | He might be there. | |
| Must | Obligation—a requirement or command | You must bring your passport. |
| Possibility—strongly expected but not certain | You must must be happy about your new job. | |
| Shall | Can be used in place of “will” in future tenses (usually for human subjects) | I shall call you later. |
| Offer or suggestion | Shall I make the tea? | |
| Obligation or command | You shall not pass. | |
| Should | Possibility—likely or expected without being certain | We should be there soon. |
| Obligation—something that is preferable or expected but isn’t necessarily required or done | People should eat fruit and vegetables. | |
| Advice or suggestion | You should tell him how you feel. | |
| Will | Future tenses:
|
She will graduate this year.
I will wake up early tomorrow. |
| Request | Will you help me? | |
| Would | Request | Would you help me? |
| Volition (past, usually negative) | She wouldn’t help me. | |
| Talking about the future in the past | I thought you would say that. | |
| Conditionals and hypothetical scenarios | If I had been there, I would have laughed. | |
| Past habits | We would meet every day for lunch. | |
| Softening an opinion or a suggestion to make it less direct or more polite | I would suggest the green dress. |
Frequently asked questions about auxiliary verbs
- Is “was” a helping verb?
-
“Was,” like other forms of “be,” can either be a main verb or a helping verb (aka auxiliary verb). As a main verb, “be” is always a stative and linking verb (e.g., “I was a doctor”). As a helping verb, it helps to form the passive voice (e.g., “the house was sold”) and progressive tenses, such as the present progressive (e.g., “I was selling my house”).
- Is it “could of” or “could have”?
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Although “could of” is sometimes used in colloquial speech, the correct form is “could have” or the contraction “could’ve.”
“Could” is a modal auxiliary verb and “have” can either be an auxiliary verb or a main verb. Modals and auxiliaries are used with a main verb to change its tense, mood, or voice. When “could have” modifies a main verb, it means that something may have been possible in the past but didn’t happen (e.g., “we could have stopped for coffee if we’d left earlier”).
- Is “is” a verb?
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Yes, “is” is a verb. It is a form of the verb “be” that is used with third-person singular subjects (e.g., “She is my best friend”).
“Is” can be used in two ways:
- As a linking verb, which is used to describe the subject’s condition, state of being, or identity (e.g., “He is a nurse;” “It is bedtime”)
- As an auxiliary verb (aka helping verb) to change the tense, mood, or voice of a main verb (e.g., “She is singing tonight”)
QuillBot’s Grammar Checker can help you make sure you’re using “is” correctly.
- Is have a verb?
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Yes, “have” is a verb. It has many meanings, most of which relate to possession or relationship (e.g., “I have a blue car;” “She has two sisters”).
“Have” is an irregular verb, which means its past tense is not formed with “-ed.” Instead, the simple past tense and past participle form is “had” (e.g., “I had a dog when I was a child”).
“Have” can also act as an auxiliary verb (aka helping verb) to form perfect verb tenses:
Tense Example Present perfect I have eaten Past perfect I had eaten Future perfect I will have eaten Present perfect progressive (present perfect continuous) I have been eating Past perfect progressive I had been eating Future perfect progressive I will have been eating “Have” is also used as an auxiliary verb in certain conditional sentences (e.g., “If I had known you were coming, I would have bought groceries”).
QuillBot’s Grammar Checker can help you make sure you’re using “have” correctly.
