Auxiliary Verbs: Definition, Examples, & Exercises

Just like nouns, verbs are an essential part of any sentence. Without either, you cannot express a complete thought. However, there are some types of verbs whose purpose is to “help” other verbs. These verbs are called auxiliary verbs. 

Auxiliary verbs cannot exist by themselves in a sentence; they must be connected to another verb. These “helping” verbs can connect to both action and linking verbs in order to add tense, mood, voice, and modality to these verbs. 

In this blog post, we will focus on learning how to recognize and use auxiliary verbs, but you can learn more about the other types of verbs on the Albert website. 

When you’re ready, test yourself with a quiz  and practice with our high-quality, standards-aligned questions here.

What We Review

An auxiliary verb “helps” the main verb of the sentence by adding tense, mood, voice, or modality to the main verb. Auxiliary verbs cannot stand alone in sentences; they have to be connected to a main verb to make sense. 

For example, a sentence that used the auxiliary verb, could, would also need a main verb for this helping verb to make sense. 

Look at the following incorrect sentence: 

Something is missing, right? There is the auxiliary verb, could, and an adverb, not, but we need the main verb, decide, for the auxiliary verb to do its job in the sentence. 

The sentence should read: “She could not decide whether she wanted to dye her hair blue or purple.” 

The auxiliary verb helps the reader understand that the girl in the sentence was unable to make a decision. The main verb cannot express this indecision without the help of the auxiliary verb. 

Since auxiliary verbs help the main verb express tense, mood, and voice, there are three different kinds of auxiliary verbs to perform these three different functions. 

These auxiliary verbs can sometimes be confused with linking verbs, so it is important to use the context of the surrounding words in the sentence, or context clues, to know which verb is being used. 

For example: 

In the sentence above, can you tell which verb is auxiliary and which is linking? 

The first was links the subject, he, to a state of being, happy, so this is a linking verb. 

The second was is followed immediately by a main verb, wearing, so this is an auxiliary verb. 

The phrase was wearing is an example of a main verb paired with an auxiliary verb showing tense. This particular verb tense is called past progressive because it expresses an ongoing action that happened in the past. 

Oftentimes, auxiliary verbs that express mood are used in sentences that ask a question or sentences that make a command. 

Here is an example interrogative sentence, or a sentence that asks a question: 

Even though this auxiliary verb is separated from the main verb by the noun subject, it is still helping the main verb by asking whether something was done yesterday or not. 

Additionally, these auxiliary verbs can be used in commands, or imperative sentences. 

For example: 

In this sentence, the auxiliary verb adds emphasis to the main verb showing that it is absolutely necessary to make sure that the dog is walked. 

Sometimes voice can refer to a writer’s specific style, but in this context, voice refers to the difference between active and passive voice. 

When a verb is written in active voice, the action is done by the subject of the sentence. 

For example: 

In this sentence, the subject, dolphin, is performing the action of the sentence, which is called. 

However, if the voice was changed from active to passive, the subject could no longer do the action and it would look like this: 

The auxiliary verb, was, allows the writer to change the voice of the sentence from active to passive while keeping the same main verb. 

There is a fourth type of auxiliary verb that expresses possibility or ability, and these are called modal auxiliaries. 

Remember the sentence about the girl wanting to dye her hair? Since she could not decide which color to use, this is an example of a modal auxiliary because it expresses ability. 

Sure, maybe if she did more research or got input from her friends she could eventually make a decision, but as it stands in the sentence, she was unable to make up her mind, making it necessary for the writer to use one of these auxiliary verbs. 

Although these four types of auxiliary verbs are used by writers for different purposes, they each help the main verb in some way, and can even be used together in the same sentence. 

As a recap of what we learned above, remember that some auxiliary verbs express tense, or when the main verb occurred. 

For example:

Also remember that other auxiliary verbs express mood, and these can be used in asking questions or making commands. 

For example: 

Additionally, auxiliary verbs can also express passive voice. If the writer wants the subject to receive the action instead of do the action in the sentence, they would use one of these auxiliary verbs to express voice. 

For example:

Finally, auxiliary verbs can express modality, which can include everything from ability, permission, likelihood, or advice. 

For example:

Here are some examples of some of these different types of auxiliary verbs being used together: 

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Here are some important tips to help you understand auxiliary verbs: 

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Now that you understand how auxiliary verbs are used in sentences, review the anchor chart below and complete the review to fully understand auxiliary verbs. 

Refer to the graphic below to learn the different types of auxiliary verbs:

This list, obviously, does not include all possible auxiliary verbs; however, it is meant to be used as a guide while identifying this type of verb.

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Now that you know some common auxiliary verbs, test your ability to accurately identify these verbs in the sentences below.

Select the auxiliary verb(s) in the sentences below. Remember, these verbs cannot stand alone in sentences and must help the main verb. 

1. The Avengers knew that if Thanos completed the Infinity Gauntlet, he would use it to wipe out humanity. 

2. Loki was planning to steal the Tesseract before Thor stopped him. 

3. The soldiers were freed by Captain America in a daring rescue mission. 

4. “Are you skipping school to participate in dangerous missions?” Tony Stark asked Peter Parker. 

5. “What would you do if you were in my shoes?” Black Widow asked Hawkeye. 

Pro tip: When evaluating whether a verb is an auxiliary verb, ask yourself these questions: 

For additional practice, check out Auxiliary Verb content on Albert.

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Feeling confident in your understanding of auxiliary verbs? 

Take this short six-question quiz to see what you’ve learned:

1. Can an auxiliary verb stand alone in a sentence? 

2. Can the same auxiliary verb help the main verb in different ways depending on how it is used in a sentence? 

3. In this sentence, does the auxiliary verb help the main verb express voice or tense? 

He was trying to explain where he was coming from before he was rudely interrupted. 

4. In this sentence, does the auxiliary verb help the main verb express voice or tense?

On Black Friday, the local mall was rushed by greedy shoppers determined to snag some great deals. 

5. In this sentence, does the auxiliary verb help the main verb express mood or modality? 

Are you working next Friday? 

6. In this sentence, does the auxiliary verb help the main verb express mood or modality? 

You should not work next Friday since you are not feeling well. 

For additional practice with auxiliary verbs, check out our practice on Albert: Auxiliary Verbs.

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While understanding auxiliary verbs may not seem to be as important as understanding action and linking verbs, the Common Core English Language Progressive Skills Chart shows that comprehension of all types of verbs is essential for all ages and levels of both readers and writers. 

For specific standards addressing these different types of auxiliary verbs, check out the Common Core State Standards site. 

Albert’s Auxiliary Verb Practice is a great tool for practicing these types of verbs, whether as an in-class or homework assignment.  Our assessments are a great tool for both pre-and post-tests to gauge student comprehension, and teachers have the ability to use either a pre-made assessment or to create their own.

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Auxiliary Verbs help the main verb by adding tense, mood, voice, and modality. 

Many auxiliary verbs can be used to help the main verb in more than one way, so pay attention to the context of the entire sentence to understand best how the auxiliary verb is being used. 

Be sure to check out our grammar course for more auxiliary verb practice. 

You can also access over 3,400 high-quality questions that address nearly every grammatical concept.

Albert has hundreds of grammar practice questions with detailed explanations to help you master concepts.