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What are Modals?

Modals are one of the most important topics you need to master if you are learning the English language.

There are so many of them and while they might seem the same in meaning, using one instead of the other might result in confusion. 

With that, please continue reading if you want to find out more about modals and when to use them. 

Modals – What are They?

Modals (also known as modal verbs, modal auxiliary verbs, or modal auxiliaries) are verbs that behave in an unusual way.

They are not like regular verbs like ‘work’, ‘play’, ‘visit’… They add to the understanding of the function of the primary verb that follows. 

Unlike other verbs that change in form by adding either -s or -es, modals do not have this characteristic. They remain as they are regardless if the subject is singular or plural. 

They are used to represent certainty, possibility, willingness, duty, necessity, and capacity and are utilized to indicate modality.

Here are the different modals in the English language:

  • can
  • could
  • may
  • might
  • must
  • shall
  • should
  • will
  • would
  • ought to
  • have to
  • need to
  • used to

What are the Functions of Modals?

It is perfectly common to have trouble understanding how modal verbs work, given their wide range of applications.

Even advanced students and native speakers occasionally fail to employ these irregular verbs. 

To help you understand modals more easily, here are the different modals with their functions. 

Note: Some modals may have more than one function. 

Modals to Show Possibility 

Employ the modal verbs ‘could’, ‘may’, or ‘might’ in situations when something is possible but not certain.

could“The package could arrive tomorrow.” 

“It could start snowing this afternoon.” 
may“It may rain today.” 

“The guests may arrive earlier than expected.” 
might“I might go to Paris this year.” 

“They might postpone the game because of the rain.” 

Modals to Express (in)Ability

The modal verb ‘can’ indicates whether or not the subject is capable of doing an action or demonstrating an ability.

Similarly, the negative form, ‘cannot’’ or can’t’, expresses the subject’s inability to perform a task.

can“I can hold my breath underwater for more than two minutes.”

“She can write with both her right and left hands.” 
cannot“He cannot speak French.”

“They cannot come to the party.”

Modals to Express Likelihood

Some things appear to be likely, but we cannot be certain. You may employ the modal verbs ‘should’ and ‘must’ to convey possibility without certainty in these situations.

Modals to Ask Permission

must“She must be rich to be able to buy such a car.”

“His parents must be proud of the person he has become.” 
should“The pizza should be here any minute.” 

“The baby should be asleep by now.”  

Begin your question with the words ‘can’, ‘may’, or ‘could’ if you wish to ask permission to accomplish anything. 

If you ask “Can I go outside?” it may be mistaken as “Do I have the capacity to go outside?” 

In more polite and formal usage, may is better for permission. However, when discussing possibility or permission, ‘may’ and ‘can’ are both entirely acceptable possibilities in modern language.

mayMay I go with you to the park?”

May I leave work early today?”
couldCould I bring a guest?”

Could I borrow some books?”
canCan I leave my things here?”

Can I help you with anything?”

Modals to Make a Request

Begin your question with ‘can’, ‘could’, ‘will’, or ‘would’ if you want to ask someone else to do anything.

willWill you turn the lights on?”

Will you help me with these books?”
wouldWould you fix the fence?”

Would you accompany me to the dentist?”
canCan you pass me the pepper?”

Can you drive me to the airport?”
couldCould you call the ambulance?”

Could you lend me some money?”

Modals to Provide Suggestion/Advice

What if you just want to suggest something rather than command it? 

You can use the modal verbs ‘should’ or ‘ought to’ to give comments or advice without ordering someone about.

should“He should wear less cologne.” 

“They should try the pasta.”
ought to“You ought to consult a doctor.” 

“You ought to bring extra money just in case.” 

Modals to Give a Command

If you wish to give someone orders, however, use the modal verbs ‘must’, ‘have to’, or ‘need to’.

must“You must leave your shoes outside.”

“You must pay before entering.” 
have to“You have to clean your room.”

“You have to keep quiet.”
need to“You need to be there before 8 in the morning.”

“You need to call the police.”

Modals to Show Obligation or Necessity

An essential activity, such as an obligation, duty, or necessity, can be expressed with modal verbs. Similarly, the negative form indicates that no action is required. 

Use the same modal verbs as directives, such as ‘must’, ‘have to’, ‘need to’, or ‘ought to’. 

must“We must wait for the clinic to open.”

“They must present their ID to the guards.”
have to“You have to tell me what happened.”

“She doesn’t have to bring a gift.”
need to“You need to take your meds every day.”

“He doesn’t need to go with them if he doesn’t want to.”
ought to“You ought to tell your parents what happened.” 

“You ought to leave your belongings outside.” 

Modals to Express a Habit

You can use the modal word ‘would’ for the past tense and ‘will’ for the present and future to show a continuing or habitual action; something the subject conducts on a regular basis. 

If you are talking about a habit that no longer exists, you can use the phrase ‘used to’.

will“I will jot down notes on each and every lecture I attend.”

“I will prepare my things ahead of time every time I have a trip.” 
would“I would visit my grandparents every summer.”

“When I was in the country, I would wake up really early to go jogging.”  
used to“I used to go fishing with my brothers when we were teens.” 

“She used to babysit her nieces when she was jobless.” 

What are the Grammar Rules of Modal Verbs?

Now that we have covered the functions of the different modals, as well as their significance in academic contexts, let us now delve further into the grammar and syntax of each modal verb. 

We have specified four areas of grammar that learners should concentrate on below.


Inflection is usually employed on verbs in the English language, and it can be used to show grammatical qualities like person, number, or tense. 

The fundamental guideline to remember with modal verbs is that, unlike other main verbs, they are not inflected to agree with the third person. 



  • I must pay the rent today.”


  • “She must be ready by 10 am.” 

NOT “She musts be ready by 10 am.” 

However, there are some modals with a third-person inflection. These are ‘be able’, ‘need to’, and ‘have to’. 



I need to call my parents.”


He has to bring his passport for the trip.”

NOT “He have to bring his passport for the trip.”


Only ‘could’ and ‘used to’, out of all the modal verbs, can be used to communicate past time references.

Because modal verbs are typically employed to refer to the present or future rather than the past, they are only used to refer to the present or future.

Thus, you may simply use the ‘have’ + ‘past participle’ perfect-aspect construction to emulate the past tense. 

“You should arrive early.”“You should have come early.”
“You must study for your exams.” “You must have studied for your exams.” 

Verb Phrases

When one verb precedes another in a verb phrase, the second verb is usually expressed as a full infinitive using ‘to’.

SubjectVerb 1Verb 2
Main VerbItry/hope/wantto learn
Modal VerbIcan/could/shouldlearn

Modal verbs like ‘can’ and ‘should’, on the other hand, frequently come before bare infinitives (uninflected main verbs without the word ‘to’ preceding them). 

Except for the three other modals listed below, this rule of eliminating ‘to’ before the second verb applies to all modal verbs:

Modal Verbs with Full Infinitives 

have to

ought to

need to









Auxiliary Nature

Because modal verbs are auxiliary (assisting) verbs, they almost always have to be used in conjunction with another verb in a sentence.

The only time modal verbs can be the lone verb in a phrase is when the speaker has assumed or omitted certain aspects of the clause. 

Can you speak Spanish?”“No, I can’t (speak Spanish).” 
“It could start later than expected.” “It could (start later than expected.”
Will you go with me to the mall?”“Yes, I will (go with you to the mall).”
Should I give her something?”“Yes, you should (give her something).”


While most verbs in the English language are negated by adding the phrases ‘do not’ or the contracted form ‘don’t’ before them, this is not always the case with modal verbs. 

couldcould notcouldn’t
maymay not
mightmight notmightn’t
mustmust notmustn’t
shallshall notshan’t
shouldshould notshouldn’t
willwill notwon’t
wouldwould notwouldn’t
ought toought not tooughtn’t to
have todoes/do not have todoesn’t/don’t have to
need toneeds/need not toneedn’t to

Question Forms

Finally, the most prevalent grammatical norm for creating questions with modal verbs is to place the modal verb before the subject.

“We should surprise our parents with a gift.”Should we surprise our parents with a gift?”
“It will be here right now.” Will it be here right now?”
“She can speak four languages.” Can she speak four languages?”

While this structure may apply to most modal verbs, the correct way when formulating questions for other modal verbs are as follows:

Note: Instead of ‘ought to’, people usually say ‘should’.

“You have to go now.” Do you have to go now?” 
“She needs to gain weight.” Does she need to gain weight?”
“I ought to be working on my project.” Should you be working on your project?”

Why are Modal Verbs Important?

Because a verb and its related nouns hold the majority of a proposition’s meaning, verbs are one of the most significant word groups in the English language. 

The following two statements, for example, show how a statement can be comprehended without any words other than verbs and nouns. 


  • “I must finish my tasks first before playing with you.”

Without modals and prepositions:

  • “I finish my tasks first before playing you.” 

Modal verbs are an important part of language learning since they are a form of auxiliary verb that accounts for 15% of all verb usage. 

While modal verbs are more frequently utilized in conversation than in academic writing, they nonetheless allow the speaker or writer to express what they actually mean. 

“You can take the day off.”

“You may not come to my party.”
“You must take the day off.”

“You should not come to my party.”

Why are Modal Verbs Challenging for Students?

Although there are a variety of reasons why English students make frequent mistakes when formulating statements that require the representation of modality, we have divided them into four categories.

  • Avoidance

Although it may be possible to evade using modal verbs completely and instead rely on modal adjectives like ‘possible’, adverbs like ‘perhaps’, or nouns like ‘probability’, an overreliance on these words and avoidance of modals will probably make a speaker’s or writer’s language appear odd or unnatural, especially to a native English speaker.

  • Grammar

Grammar for modals can occasionally cause students to make errors, resulting in miscommunication. 

Since modal verbs do not have the inflection of more common lexical verbs, they frequently utilize present and past tense forms like ‘can’ and ‘could’ for purposes other than demonstrating a timeframe, and they rarely precede full infinitives using ‘to’.

It is understandable that some students make numerous errors with this word type.

  • Pronunciation

When used in connected speech, modal verbs can be pronounced in strong or weak forms, and because such verbs are most typically spoken in their weak forms when paired with another verb, non-native English speakers may struggle to recognize them. 

While not hearing or understanding a modal verb has little impact on overall comprehension, some constructions can cause difficulties.

If the word ‘can’ is missing from the offer below, for example, the listener may understand the remark as a promise:


  • Offer:

“I can help you with your errands.”

  • Promise: 

“I (?) help you with your errands.” 

  • Selection

Because the same modal verb can be used to indicate a variety of functions, and because multiple modal verbs can indicate the same function, a non-native English speaker may either (a) choose the wrong modal verb for their utterance, or (b) overuse the same modal verb when an alternative verb would have been more appropriate.

Exercises on the Use of Modals

Now that we have covered the different modals, their uses, and the rules that you need to follow when employing them in your sentences, it is now time for you to check whether or not you can now use them correctly. 

Here are some practice questions about modals for you to understand them better. 

  1. I am attending university now. My teacher in Literature ______________ speak English, Spanish, Italian, and Portuguese. 
  • can
  • may
  • should

  1. The professor is a punctual person. You ______________ arrive at the venue before the lecture starts. 
  • can
  • may
  • must

  1. Bring an umbrella. It ______________ rain layer. 
  • might
  • should
  • needs to

  1. He has been working for ten hours now. He ______________ be exhausted. 
  • can
  • must
  • has to

  1. You ______________ be joking! That’s impossible!
  • would
  • should
  • have to

  1. The book is not required. If we wanted extra credit, my lecturer stated we may read it. However, we ______________ read it if we don’t wish to. 
  • would not
  • should not
  • don’t have to

  1. My grandfather is ninety-two but he ______________ still read without using eyeglasses. 
  • can
  • may
  • should

  1. Back in the day, there was a time when I ______________ stay up until midnight partying with my friends.
  • must
  • shall
  • would

  1. You ______________ try to lose weight anymore. Your weight is fine. 
  • can not
  • will not
  • should not

  1. ______________ stand on your head for more than five minutes? I don’t think so. 
  • Can
  • May
  • Will

  1. This is a public place. You ______________ not smoke in her. 
  • may
  • should
  • have to

  1. Last week, I ______________ cram big time for my finals. I’m glad it’s over now. 
  • must
  • should
  • had to

  1. You ______________ do the job well if you don’t speak fluent German. 
  • can’t
  • shan’t
  • wouldn’t

  1. I have called the ambulance. The paramedics ______________ be here any moment now. 
  • must
  • should
  • have to

  1. ______________ you mind if I use your old room? 
  • Would
  • Could
  • Should

  1. Our country ______________ host the Olympics next year. I’m excited. 
  • must
  • might
  • should

  1. Her flight took twelve hours. She ______________ tired. 
  • can be
  • must be
  • should be

  1. The people at the general admission area ______________ see the artists anymore because they are too far.
  • couldn’t
  • wouldn’t 
  • shouldn’t

  1. You ______________ excuse yourself from the dinner if you don’t feel well. They will understand. 
  • may
  • might
  • have to

  1. I ______________ take off. It’s late and my parents are waiting. 
  • can
  • may
  • should

Answer Key

  1. can
  2. must
  3. might
  4. must
  5. have to
  6. don’t have to
  7. can
  8. would
  9. should not
  10. Can
  11. Should
  12. had to
  13. can’t
  14. should
  15. Would
  16. might
  17. must be
  18. couldn’t
  19. may
  20. should

Additional FAQs  —  Modals and Their Usage

Why Do We Need to Use Modals? 

We need to use modals so we can understand each other better. Modals help us to make our message clearer. 

For example, we cannot use the modal ‘ought to’ if we are only making a suggestion (as in “You ought to leave now”, instead of “You may leave now”), because it may sound more like a command. 

Do Modals Have Singular and Plural Forms?

Most modals do not have singular and plural forms.
They do not change their form, therefore they are the same in all three persons. 

These modals are ‘could’, ‘may’, ‘might’, ‘must’, ‘shall’, ‘should’, ‘will’, ‘would’, and ‘ought to’.

However, the modals ‘have to’ and ‘need to’ are exceptions and have to agree with their subject, whether singular or plural. 

Where are Modals Placed in a Sentence? 

Modal verbs are always placed before the main verb. 

Employ the infinitive form of the main verb without ‘to’ when using modal verbs.

For questions, they are placed at the beginning of the sentence.


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