Explore this Comprehensive Guide to Auxiliary Verbs: Definition & examples to enhance your understanding of English grammar and usage.

Comprehensive Guide to Auxiliary Verbs: Definition & examples

Improve your grammar skills of Modal auxiliary verbs and functions. This post on modal auxiliary verbs and their functions will enable you to speak English well.

What is a verb?

The verb is a very essential part of a sentence. Without a verb, we cannot indicate the action of the subject. A verb shows all actions including feelings and emotions.

Definition of a verb -

“A word or phrase that describes an action, condition, or experience”. (Cambridge Dictionary).

We can classify verbs according to what kind of action they signify.

Verbs referring to action are called action verbs.

E.g. run, walk, drink, write, speak, etc.

Some verbs refer to feelings and emotions.

E.g. know, feel, love, hate, believe, etc.

Some verbs refer to state (being) or condition

E.g. am, is, are, etc.

We classify verbs into many types according to their function or role in a sentence or context.

Auxiliary Verbs/Helping Verbs.

Auxiliary verbs or helping verbs help another verb to make it sensible and meaningful. It changes the other verb’s tense, mood or voice.

There are 24 auxiliary Verbs.

am, is, are, was, were, have, has, had, do, does, did, shall, should, will, would, can, could, may, might, must, used to, ought to, need and dare

11 out of them [am, is, are, was, were, have, has, had, do, does, did] are primary auxiliary

and the remaining 13 [shall, should, will, would, can, could, may, might, must, used to, ought to, need and dare] are Modals or modal auxiliary Verbs.

Primary auxiliary Verbs

Root verb	Auxi. verb	Use in a sentence
to be	am	I am a student
to be	is	She is my mother.
to be	are	They are my friends
to be	was	She was absent yesterday.
to be	were	The fruits were expensive.
to have	have	I have two hands.
to have	has	She has black hair.
to have	had	We had two pets - a dog and a parrot.
to do	do	I do my work honestly.
to do	does	She does the homework regularly.
to do	did	She did her best to win the trophy.

These verbs are called primary auxiliary verbs because they can be used on their own as well as they can help the other verb.

E.g. I have a pen. (Used as a main verb)

I have seen that picture. (Here, the verb have is helping the main verb 'seen'.) }.

For the use of primary auxiliary verbs as helping verbs go to the Master 12 tenses post. You will better understand how they help the main verb or action verb,

The remaining 13 verbs (out of 24) are Modal auxiliary Verbs.

Modal auxiliary verbs

Modals are not used alone. They always help the main verbs or action verbs.

E.g. We cannot say - I can a picture.

I can draw (or paint or see or colour) a picture.

The list of modal auxiliary verbs with examples and their meanings in Hindi (for better understanding)-

Modals

Meaning in Hindi

Example

shall

गाऊंगा /गाएगा

I shall sing a song.

will

गाएगी/गाएगा

She will sing a song.

should

गाना चाहिए

You should sing a song.

would

गाती थी/ गाता था

They would sing a song.

can

गा सकता/सकती

I can sing a song.

could

गा सका/सकी

My mother could sing a song
at the party though she was ill.

may

गा सकता/सकती

May I sing a patriotic song?

might

गा सकता/सकती

I might sing a song, but I am not sure.

must

गाना ही चाहिए

You must sing a song.

used to

गाती थी/था

She used to sing songs for the movies.

ought to

गाना चाहिए

You have a melodious voice.
You ought to sing a song.

need

She need not sing a song.

dare

How dare you come here?

Modals and their Functions.

Shall and will -

Shall and will - to express a pure future.
Shall is used in the first person ( I/we shall ) and will in the second and third persons.
Shall is used in the second and third persons to command or to promise.
But these uses of shall are old-fashioned and formal In present-day English, however, we use will commonly for all persons.
In modern especially in American English shall is used in the second and third persons to know about the will of the person.

Future Intention:

Traditional: We shall go to the museum this weekend.

Modern: We will go to the museum this weekend.

Promise:

Shall: I shall always stand by you.

Will: I will always stand by you.

Determination:

Shall: You shall not pass! (Command)

Will: I will find a way to solve this problem.

Offer/Suggestion:

Shall: Shall I help you with your luggage? (Offer)

Will: Will you be joining us for dinner? (Question about future plans)

Command/Instruction:

Shall: The meeting shall commence at 10 AM sharp. (Formal instruction)

Will: You will submit the report by Friday.

Should-

The modal auxiliary "should" is versatile and widely used to express advice, expectations, obligations, and more.

Expressing Advice or Suggestions

You should study more if you want to pass the exam.
They should visit the doctor if they’re not feeling well.
We should leave early to avoid traffic.

Expressing Obligation or Duty

People should respect the environment.
You should apologize for your mistake.
Employees should adhere to company policies.

Expressing Expectation - Should" can also indicate something that is expected or likely to happen.

The train should arrive in a few minutes.
The weather should be sunny tomorrow.
He should be here by now.

Expressing Conditional Ideas - In conditional sentences, "should" can be used in the "if" clause to indicate a less likely condition or to add a level of politeness.

If you should see him, tell him to call me. (Less likely condition)
Should you need any help, feel free to contact us. (More polite)

Expressing Politeness - "Should" can be used to make polite requests or ask for advice, often with a more formal tone.

Should I open the window? (Asking for advice)
Should we wait for them before starting dinner? (Polite request)

Giving Instructions or Orders - While not as forceful as "must," "should" can be used to give instructions or orders, often in a more suggestive or polite manner.

You should follow the instructions carefully.
Students should submit their assignments by Friday.
You should not leave your personal belongings unattended.

Expressing Regret or Criticism - Should" can express regret about a past action or criticize an action that didn't happen but was expected or needed.

You should have called me before making a decision. (Regret)
They should have been more careful with their investments. (Criticism)

Comparison with "Must": "Should" is less strong than "must." "Must" indicates a necessity or requirement, while "should" suggests a recommendation or expectation.

You must wear a helmet. (Requirement)
You should wear a helmet. (Recommendation)

Formality: "Should" is more formal than "ought to" and is often used in professional, academic, or written contexts.

Would

'Would', can express politeness, hypothetical situations, habitual past actions, and more.

1. Politeness and Requests: 'Would' is used to express polite requests.

Examples:

Request: Would you pass me the salt, please?
Offer: Would you like some tea?

[In questions, "would" is more polite than "will."

Polite Question: Would you help me with this?
Direct Question: Will you help me with this?]

2. Expressing a Hypothetical or Imaginary Situation-

'Would' is used to talk about hypothetical situations or actions that are imagined or not real. It’s commonly found in conditional sentences, particularly in the second (unreal present) and third (unreal past) conditionals.

Examples:

Second Conditional: If I won the lottery, I would buy a house. (Imaginary situation in the present or future)
Third Conditional: If I had known about the party, I would have gone. (Imaginary situation in the past)

"Would" is also used to talk about something that might happen in an imagined scenario.

Example: It would be great if you could join us. (Imaginary or wished-for scenario)

3. Expressing a Habitual Action in the Past

"Would" can be used similarly to "used to." to show repeated actions in the past but no longer occur in the present.

Examples:

Every summer, we would go to the beach.
My grandfather would always tell us stories by the fire.

Note: While "would" can describe habitual past actions, "used to" is more flexible and can describe both habitual actions and states in the past.

Example: I used to live in New York. (Describes a past state, where "would" wouldn't be appropriate.)

4. Expressing a Future in the Past

"Would" is used to talk about something that was in the future from a past perspective. This usage occurs in reported speech or when recounting past events where the speaker looks ahead to a future event.

Examples:

He said he would finish the project by tomorrow. (Future from the past point of view)
She knew it would rain later. (Anticipation of a future event from a past time)

5. Expressing Desire or Willingness

"Would" can express a willingness or desire to do something. In this context, it often appears with verbs like "like," "love," "hate," etc.

Examples:

I would love to visit Paris someday.
She would hate to miss the concert.

This usage also applies when making polite offers or expressing desires indirectly.

Example: I would like a cup of coffee, please.

6. Giving Advice or Making Suggestions

"Would" can be used to give advice, particularly when the speaker is offering a suggestion based on what they would do in the same situation.

Examples:

I would recommend trying the new restaurant.
If I were you, I would apologize.

7. Expressing Expectations or Assumptions

"Would" can also express what the speaker expects or assumes to happen, often based on past experience or logic.

Examples:

He would be the one to forget his keys. (Expectation based on a person's known behaviour)
That would explain why she’s late. (Logical assumption)

8. Expressing a Wish

"Would" is used in expressions of wishes, particularly in the construction "I wish" followed by "would" to express a desire for someone or something to change in the future.

Examples:

I wish you would stop smoking.
She wishes he would call more often.

This use often conveys a sense of frustration or impatience with the current situation.

9. Softening Statements or Offers

"Would" can be used to soften statements, making them less direct or assertive, and more tentative.

Examples:

I would say that this is the best option.
It would seem that we have a problem.

This usage makes the statement sound less definitive, often used to be polite or avoid confrontation.

10. Expressing Uncertainty or Tentative Actions

In some cases, "would" is used to express uncertainty or actions that are tentative and not yet confirmed.

Examples:

I would think it’s going to be cold tonight. (Uncertainty about the future)
She would probably agree with us. (Tentative assumption)

11. Conditional Sentences

"Would" is essential in conditional sentences, particularly in the second and third conditionals, as mentioned earlier.

Second Conditional (Present/Future Unreal): If I were rich, I would travel the world.
Third Conditional (Past Unreal): If she had known, she would have acted differently.

These conditionals are used to express hypothetical situations and their possible outcomes.

Can:

It expresses ability, permission, possibility, and more.

1. Expressing Ability

'Can' refers to both physical and mental capabilities.

Examples:

Physical Ability: She can swim very fast.
Mental Ability: He can solve complex math problems.

2. Expressing Impossibility or Inability

When used in the negative form ("cannot" or "can’t"), "can" expresses inability or impossibility.

Examples:

I can’t lift this heavy box. (Inability)
You can’t park here. (Impossibility or lack of permission)

3. Asking Questions About Possibility or Ability

"Can" is frequently used to ask questions about someone’s ability to do something or about the possibility of something happening.

Examples:

Can you play the piano? (Asking about ability)
Can it really be true? (Asking about possibility)

4. Expressing Permission

"Can" is also used to give or ask for permission in a more informal context.

Examples:

Giving Permission: You can leave the classroom now.
Asking for Permission: Can I borrow your pen?

5. Difference Between "Can" and "May":

While "may" is traditionally considered more polite or formal, "can" is commonly used in everyday speech to request or grant permission.

Formal: May I go to the bathroom?
Informal: Can I go to the bathroom?

"Can" is interchangeable with "may," although "may" is considered more formal.

6. Expressing Prohibition (Negative Form)

While "can" typically suggests permission or ability, the negative form ("can’t") is often used to prohibit or forbid something informally.

Examples:

You can’t smoke here. (Prohibition)
You can’t use your phone during the exam.

7. Expressing Possibility

"Can" is used to express the possibility that something might happen, especially when discussing what is generally possible under certain conditions.

Examples:

It can be very cold in winter.
Driving in the rain can be dangerous.

In these examples, "can" does not refer to ability but rather to something that is possible under certain circumstances.

8. Expressing Requests

"Can" is often used to make requests, although, as with asking for permission, this use of "can" is informal.

Examples:

Can you pass the salt?
Can you help me with this task?

Again, "can" is more casual compared to "could" or "would," which are often used to make more polite or formal requests.

9. Difference Between "Can" and "Could":

"Can" refers to present ability or possibility, while "could" is used for past ability or to make polite requests and suggestions.

Present Ability: I can swim.
Past Ability: I could swim when I was a child.
Polite Request: Could you open the window?

Could

"Could" is the past tense form of "can" and is used in various contexts to express possibility, ability, permission, suggestions, and requests.

1. Expressing Past Ability

"Could" is used to talk about someone’s ability to do something in the past.

Examples:

She could swim when she was a child.

I could read before I started school.

2. Making Polite Requests

"Could" is commonly used to make polite requests. It is more formal and polite than "can."

Examples:

Could you please pass the salt?

Could you help me with this problem?

3. Expressing Suggestions

"Could" can be used to make suggestions or offer ideas in a gentle way.

Examples:

We could go to the park if you like.

You could try restarting the computer to solve the problem.

4. Expressing Hypothetical Situations

"Could" is used in conditional sentences to express hypothetical situations, particularly when talking about what might happen under certain conditions.

Examples:

If I had more time, I could help you with your project.

She could win the competition if she practices hard.

5. Polite or Tentative Offers and Suggestions

"Could" is used to make offers or suggestions in a polite and tentative way, often to avoid coming across as too assertive.

Examples:

I could lend you some money if you need it.

We could watch a movie tonight.

6. Expressing Doubt or Uncertainty

"Could" is sometimes used to express doubt or uncertainty about a situation or fact.

Examples:

I could be wrong, but I think the meeting is at 3 PM.

He could be lying, but I’m not sure.

7. Use in Reported Speech:

When "can" is used in direct speech and the reporting verb is in the past, it changes to "could."

Direct Speech: She said, "I can help you."

Reported Speech: She said she could help me.

8. Difference Between "Could" and "Would":

"Could" refers to potential ability or possibility, whereas "would" expresses a willingness or intention.

Could: I could go to the party if I finish my work.

Would: I would go to the party if I had an invitation.

9. Expressing Regret:

"Could have" (followed by a past participle) is used to express regret or a missed opportunity.

Examples:

I could have won the race if I had trained harder.

She could have been a great singer.

{Note:- Use was were able to, not could, when dealing with a purpose achieved. Could not be used as the past equivalent of can expressing ability always.

For example, you should not say 'Yesterday I could solve the maths sums '; you should say 'Yesterday I was able to solve maths sums'. }

Must

Must has only one modal form. It is used to express compulsion or necessity.

ZE.g. A servant must obey his master.