What are auxiliary verbs?

Auxiliary verbs, are helping verbs that modify the meaning of the main verbs in a clause. They are used to make tenses, interrogatives, negatives, passives, and to add emphasis.

There are two categories of auxiliary verbs, primary auxiliary verbs and modal auxiliary verbs. Here, we will focus on primary auxiliary verbs.

Primary Auxiliary Verbs

The most commonly used primary auxiliary verbs are forms of do, be, and have. These verbs can also function as main verbs. In addition, a clause can contain one or more auxiliary verbs.

Creating Verb Tenses

Auxiliary verbs are used to create continuous and perfect verb tenses. To illustrate this we’ll start off with a short sentence in the present simple tense, “Sally swims.”

Subject	Verb
Sally	swims.

(affirmative present simple tense)

There is only one verb in the sentence (swims). Since auxiliary verbs are always used with a main verb, there aren’t any auxiliary verbs in this sentence.

Present Continuous

Sally is swimming.

In this example in the present continuous tense, we add the auxiliary verb is, which is a form of be. The suffix “-ing” gets added to the main verb.

Subject	Auxiliary Verb	Verb
Sally	is	swimming.

(affirmative present continuous tense)

Past Continuous

Sally was running.

In this example in the past continuous tense, we add the auxiliary verb was which is a past form of be. The suffix “-ing” gets added to the main verb.

Subject	Auxiliary Verb	Verb
Sally	was	swimming.

(affirmative past continuous tense)

Present Perfect Simple

Sally has run.

Subject	Auxiliary Verb	Verb
Sally	has	swum.

(affirmative present perfect simple tense)

In this example in the present perfect simple tense, we add the auxiliary verb has, which is a form of have. The main verb, swum, is in the past participle form.

Past Perfect Continuous

Sally had been swimming.

In this example in the past perfect continuous tense, we add the auxiliary verbs had and been, which are forms of have and be. The suffix “-ing” gets added to the main verb.

Subject	Auxiliary Verb	Auxiliary Verb	Verb
Sally	had	been	swimming.

(affirmative past perfect continuous tense)

There are more tenses that are created using auxiliary verbs. These are merely a few examples.

Creating Interrogative Sentences

The auxiliary verb do is added to sentences in the present simple tense and the past simple tense to form an interrogative sentence, or in layman’s terms, a question. In these tenses, the auxiliary verb is inverted with the subject.

Present Simple

Sally swims. (affirmative sentence)
Does Sally swim? (interrogative sentence)

To form a question, the auxiliary verb does is added before the subject. Notice the main verb eat is no longer conjugated as in the affirmative sentence. The auxiliary verb do changes to does.

Auxiliary Verb	Subject	Verb
Does	Sally	swim?

(interrogative present simple tense)

Past Simple

Sally swam. (affirmative sentence)
Did Sally swim? (interrogative sentence)

To form a question, the auxiliary verb did is added before the subject. Notice the main verb swim is no longer in the past form in the interrogative sentence. The auxiliary verb do changes to did.

Auxiliary Verb	Subject	Verb
Did	Sally	swim?

(interrogative past simple tense)

Forming Negative Sentences With “Not”

Auxiliary verbs are used with the adverb not to form negative sentences. The contracted form of not (n’t) is commonly used in spoken English.

Sally swims. (affirmative sentence)
Sally does not swim. (negative sentence)
or
Sally doesn’t swim. (negative sentence)

To form a negative, the auxiliary verb does and the adverb not are added between the subject and the verb. The main verb swim is no longer conjugated as in the affirmative sentence. The auxiliary verb do changes to does.

Subject	Auxiliary Verb		Verb
Sally	does	not	swim?
Sally	doesn’t		swim

(negative present simple tense)

Quick Tip

If there are more than two auxiliary verbs in a sentence, the adverb not goes with the auxiliary verb closest to the subject. This can be especially confusing if the main verb is a form of do, be, or have.

Sally will have had two exams by this time tomorrow. (affirmative sentence)

Sally will not have had two exams by this time tomorrow. (negative sentence)
~~Sally will haven’t had two classes by this time tomorrow.~~
~~Sally will have hadn’t two classes by this time tomorrow.~~

Forming Passive Sentences

Auxiliary verbs are used when we form sentences in the passive voice. We often use the passive voice to emphasize the action and focus less on who or what did the action.

There aren’t any auxiliary verbs in the active sentence “Sally won the race.”

Subject	Verb	Object
Sally	won	the race.

(affirmative past simple tense – active voice)

However, when we change this sentence into the passive voice, we

Subject	Auxiliary Verb	Verb
The race	was	won.

(affirmative past simple tense – passive voice)

Emphatic Use of “Do”

The auxiliary verb do can be used to create emphatic sentences that emphasize the fact that an action was done or something happened.

I eat healthy food. (no emphasis)
I do eat healthy food. (emphasizes the fact that the speaker eats healthily)

Subject	Auxiliary Verb	Verb	Object
I	do	eat	healthy food.

(emphatic use of do in the present simple tense)

Learn more about different types of verbs

Learning about different kinds of verbs can enhance your understanding of English.

Let us know what you think!

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