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Auxiliary Verbs
What Are Auxiliary Verbs? (with Examples)
An auxiliary verb is used with a main verb to help express the main verb's tense, mood, or voice. For example (auxiliary verbs highlighted, main verbs in bold):- Tense. The tense of a verb tells us when the action took place.
- Sally was eating the cake.
- Mood. The mood of a verb tells us how it is to be regarded (e.g., as a fact, a command, a wish).
- Do eat the cake, Sally.
- Voice. The voice of a verb tells us whether the subject is acting or being acted upon.
- The cake was eaten by Sally.
- to be: am, is, are, was, were, being, been, will be
- to have: has, have, had, having, will have
- to do: does, do, did, will do
Table of Contents
- Examples of Auxiliary Verbs Expressing Tense
- Examples of Auxiliary Verbs Expressing Voice
- Examples of Auxiliary Verbs Expressing Mood
- Examples of Modal Auxiliary Verbs
- Why Auxiliary Verbs Are Important
- Printable Test

Examples of Auxiliary Verbs Expressing Tense
Here are some examples of auxiliary verbs expressing tense. In these examples, the main verbs are in bold and the auxiliary verbs are highlighted.- She was waiting for an hour.
- She is waiting in the hall.
- She will be waiting outside. (In each of these examples, the auxiliary verb to be helps to form the progressive tense, which is the tense used for ongoing actions.)
- She had drunk it before we arrived.
- She has drunk it already.
- She will have drunk it by then. (In each of these examples, the auxiliary verb to have helps to form the perfect tense, which is the tense used for expressing an action's completion.)
- She had been studying before the incident.
- She has been studying.
- She will have been studying for a month at that point. (In each of these examples, the auxiliary verbs have and been help to form the perfect progressive tense, which is the tense used for expressing an ongoing action's completion.)
Examples of Auxiliary Verbs Expressing Voice
Here are some examples of auxiliary verbs expressing voice.- Our dessert was eaten by the dog.
- The geese are driven through the snicket.
- The phone will be disconnected tomorrow. (In these examples, the auxiliary verb to be helps to form the passive voice. A verb is said to be in the passive voice when its subject does not perform the action of the verb but has the action done to it.)
Examples of Auxiliary Verbs Expressing Mood
Here are some examples of auxiliary verbs being used to express mood.- Did you win? (Here, the auxiliary verb to do is used to form the interrogative mood, i.e., to ask a question.)
- Don't forget your wallet. (Here, the auxiliary verb to do (in its negative form) is used to form the imperative mood, i.e., to give an order.)
Examples of Modal Auxiliary Verbs
Let's now look at the modal auxiliary verbs. Modal auxiliary verbs combine with other verbs to express ideas such as necessity, possibility, intention, and ability. In each example below, the verb phrase is in bold and the modal auxiliary verb is highlighted.Modal auxiliary verbs expressing necessity:
- It is during our darkest moments that we must focus to see the light. (Greek philosopher Aristotle)
- I don't say we all ought to misbehave, but we ought to look as if we could. (Actor Orson Welles)
- A baby is God's opinion that life should go on. (American Poet Carl Sandburg)
- It is never too late to be what you might have been. (George Eliot)
- If there were no bad people, there would be no good lawyers. (Author Charles Dickens)
- We shall heal our wounds, collect our dead and continue fighting. (Founding father of the People's Republic of China Mao Zedong)
- No one can feel as helpless as the owner of a sick goldfish. (Cartoonist Kin Hubbard)
- Well, either side could win it, or it could be a draw. (Football manager Ron Atkinson) (Sometimes, more than one sense is expressed. Here, could expresses both ability and possibility.)
- I have inspiration. If I was educated, I would be a damn fool. (Musician Bob Marley) (That should be were educated, Bob. Just sayin'.)
- I really like vampire books. I might have a problem. (Irish writer Sarah Rees Brennan)
- If you can dream it, you can do it. (Enzo Ferrari)
- Rose has been drinking heavily since breakfast. (The adverb heavily is not part of the verb phrase.)
- Peter is definitely taking you to the airport. (The adverb definitely is not part of the verb phrase.)
That said, there are three noteworthy points related to auxiliary verbs.
(Point 1) Don't write could of, should of, or would of.
If you ever write could of, should of, or would of, you're toast. It's a writing howler. It's could've (a contraction of could have), should've (should have), or would've (would have).(Point 2) Use can for ability and may for permission.
Can is a modal auxiliary verb meaning to be able to. May is a modal auxiliary verb meaning to be permitted to.- I can whistle. (I have the ability to whistle.)
- May I have a biscuit? (Am I permitted to have a biscuit?)
- "Can I go outside, grandma?"
- "You can, dear. You're just not allowed."
- Can I have a biscuit, grandma?
- "You can, dear. You're just not allowed one." (Can is fine here, but, hey, it's still a grandma's job to issue a "correction.")
(Point 3) Expand can't to cannot not can not.
Cannot (one word) is the most common expansion of the contraction can't.- You cannot escape the responsibility of tomorrow by evading it today. (US President Abraham Lincoln)
- There cannot be a crisis next week. My schedule is already full. (US statesman Henry Kissinger)
- I cannot do it! (Can't is usually expanded to cannot.)
- I can not do it! (This is considered more emphatic.)
- Kevin can not only rap but dance too. (Here, can not must be written as two words. It's not an expansion of can't.)
- Don't write could of, should of, or would of. Just don't.
- To keep your grandchildren grammatically pure, correct their use of "Can I" to "May I" when they're seeking permission.
- Expand can't to cannot not can not unless you're trying to be really emphatic. (Bear in mind that your readers will probably just think you've misspelt cannot.)
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