---

Modal auxiliary verbs are special helper verbs that work with other verbs (main verbs and auxiliary verbs like be and have) to express things like possibility, necessity, ability, permission, and advice.

Modal verbs have unique properties that make them particularly useful for expressing attitudes, opinions, and ideas beyond simple facts. Instead of just stating that something happens, we use modal verbs to show whether something is possible, necessary, or likely to happen, or whether someone is capable of something.

For example:

• Sarah speaks French. (simple fact)
  
  
• Sarah can speak French. (the modal verb can showing ability to speak French)

Modal Verbs

can – ability, possibility, requests, permission, offers	could – past ability, polite requests, hypothetical situations
may – polite permission, possibility	might – less certain possibility, suggestions
shall – future, polite offers & suggestions	should – advice, obligation, expectations
will – future, willingness, decisions/choices	would – hypothetical situations, polite requests, past habits, preferences
must – necessity, obligation, assumptions	Semi-modals: used to / need to / have to / be able to / be supposed to

---

---

• Modal Verbs in Use

  • You can park here for free on Sundays. (ability)
    
    
  • I could stay up all night when I was in college. (past ability)
    
    
  • May I use your phone? (formal permission request)
    
    
  • It might rain this afternoon. (possibility)
    
    
  • We must finish this project by Friday. (necessity)
    
    
  • You should try the chocolate cake. (advice)
    
    
  • I will help you move house next weekend. (future promise)
    
    
  • Would you like some coffee? (polite request)

  ---

  * Modal Verbs

Contractions with Modal Verbs

Modal verbs combine with other words to create shortened forms called contractions. These shortened forms are common in casual speech and informal writing.

Positive Contractions

Positive contractions occur with will and would when they are paired with subject pronouns.

Modal Verbs: Positive Contractions

Pronoun	Will	Would
I	I will > I’ll	I would > I’d
You	You will > You’ll	You would > You’d
He	He will > He’ll	He would > He’d
She	She will > She’ll	She would > She’d
It	It will > It’ll	It would > It’d
We	We will > We’ll	We would > We’d
They	They will > They’ll	They would > They’d

Examples:

• I’ll be there in ten minutes. (will contraction)
• We’ll have to leave soon. (will contraction)
• I’d rather have tea than coffee. (would contraction)

Negative Contractions

Negative contractions combine modal verbs with not. Unlike positive contractions (which only happen with will and would), most modal verbs can form negative contractions.

Modal Verbs: Negative Contractions

Modal Verb	Negative Form	Contraction
can	cannot	can’t
could	could not	couldn’t
may	may not	(no contraction)
might	might not	mightn’t
must	must not	mustn’t
shall	shall not	shan’t
should	should not	shouldn’t
will	will not	won’t
would	would not	wouldn’t

Notes:

1) Shan’t is uncommon in modern British English and even rarer in American English. The word won’t is typically used instead.

2) May doesn’t have a contracted form. We always write may not as two words.

Examples:

• I can’t drive a manual car. (cannot)
• You shouldn’t eat so much sugar. (should not)
• She won’t be coming to dinner. (will not)
• We mustn’t be late for the meeting. (must not)

Quirks of Modal Verbs

Modal verbs don’t follow the same rules as regular verbs. They have their own grammatical patterns for things like verb forms, questions, and negatives. However, once you know these patterns, modal verbs become much easier to use.

Always Followed by Base Form Verbs

Modal verbs are always followed by the base form of the main verb they are modifying.

The base form is the simplest form of the verb – no to, no -s, no -ing, no -ed (e.g., help, love, go, arrive).

Examples:

No Third Person -s

Modal verbs stay the same for all subjects.

With regular verbs, we add -s for he, she, and it (e.g., He works / She runs / It costs), but modal verbs don’t take -s.

Example:

✅ – He can swim really well.
❌ – He cans swim really well.

Modal Verbs Don’t Change Form

This lack of change goes even further. Modal verbs don’t change at all. They don’t have -ed endings for past tense, -ing forms, or past participle forms.

This means we don’t use:

❌ – I canned swim / she musted go (-ed forms for past tense)
❌ – I am canning / she is musting / they are shalling (present participle forms)
❌ – have canned / have musted / have shalled (past participle forms)

Can Modals Show Tense?

Other verbs change form to show different tenses (walk / walked, take / took).

Modal verbs don’t take past or future endings, so the question is: can they still indicate tense? The short answer is yes and no.

Modals can be used to relate to different time periods, but they don’t show tense in the traditional sense.

Rather than indicating when something happens, modal verbs mainly focus on expressing the speaker’s attitude about what’s possible, necessary, likely, or advisable.

Since modal verbs express attitudes about what might happen or should happen rather than facts about what did happen, they’re naturally suited to present and future contexts.

– Could and Would: Past Forms

Arguably, only could and would refer to past time on their own.

• I could swim when I was five. (could as past tense of can – past ability)
• We would go there every summer. (would as past tense of will – past habit)

However, these same modals have many non-tense functions. For instance, could can also make polite requests (e.g., Could you help me? – present). Would can express hypotheticals (e.g., I would go if I had time. – hypothetical future).

Even when modals refer to the past, they’re still primarily expressing modality (possibility, necessity, likelihood, etc.) rather than marking time like other verbs do (e.g., walked / took).

– Context is Key

With could and would, it’s actually the surrounding words and sentence structure that tell us when something is happening:

• She would visit every Sunday when we lived nearby. (past habit – context shows past)
• She would visit every Sunday if she lived closer. (hypothetical future – context shows condition)

The modal would stays the same, but the context completely changes the time reference. This is different from regular verbs like ran or saw, which show past time by their form. Since modals need context to show time, some grammarians question whether they really show past tense at all.

– Other Modals and the ‘Have + Past Participle’ Construction

Modal verbs other than could and would (e.g., must / should / shall / may) have no past tense forms.

When we need these modals to refer to past time, we need to use the ‘modal + have + past participle‘ construction:

• You should have called a doctor. (past advice)
• They might have left already. (less certain past possibility)
• She must have forgotten. (past assumption)
  
  * Modal Verbs / Have / Past Participles

Modal Verbs by Function

Modal verbs express different types of meaning depending on the context. We can group these meanings into several main categories that can better help us understand when and how to use each modal verb.

Ability, Possibility, and Assumptions

Can expresses present ability or possibility:

• My sister can play the violin beautifully. (ability)
• Can you reach the top shelf? (ability)
• Temperatures can drop below freezing in December. (possibility)

Could is used to show past ability:

• He could play chess well as a child.
• She could run a marathon in under three hours.
• He could eat pizza every day and never gain weight.

May and might both express possibility, with might suggesting less certainty:

• The package may arrive by Thursday. (possibility)
• The concert might be cancelled due to rain. (less certain possibility)

Must can also express assumptions or deductions based on evidence:

• The lights are on – someone must be home. (assumption based on evidence)
• This must be expensive. (assumption)
• She must be the new manager. (deduction)

Permission, Requests, and Offers

Can asks for or gives permission and makes offers:

• Can I leave work early today? (asking for permission)
• Yes, you can leave work early today. (giving permission)
• You can borrow my laptop for the presentation. (offer)
• Can I get you anything from the kitchen? (offer)

Could makes polite requests:

• Could you explain that again, please?
• Could I have a moment to think about it?
• Could you move your car from the driveway?

May asks for and grants formal permission:

• May I ask a quick question? (asking for formal permission)
• May we use the conference room this afternoon? (asking for formal permission)
• Employees may take breaks every three hours. (granting formal permission)

Shall makes polite offers and suggestions (especially in British English):

• Shall I make us some tea? (polite offer)
• Shall I call a taxi for you? (polite offer)
• Shall we start the meeting now? (suggestion)

Obligation and Advice

Must expresses strong necessity or obligation, often coming from rules or internal conviction:

• All visitors must sign in at reception.
• I must complete this assignment tonight.
• Passengers must fasten their seatbelts during take-off.

Should expresses advice or soft obligation:

• You should back up your files regularly. (advice)
• You should exercise regularly to stay healthy. (advice)
• We should confirm our reservation tomorrow. (soft obligation)

Suggestions

Might makes tentative suggestions:

• You might want to ask your doctor about that.
• You might want to double-check your work.
• You might want to bring an umbrella.

Future and Prediction

Will shows future actions and predictions:

• The conference will begin at nine o’clock. (future action)
• This investment will pay off eventually. (prediction)
• Scientists predict robots will perform most jobs in the future. (prediction)

Will can also express willingness to do something or choices in the moment that relate to the future:

• I’ll take the rubbish out. (willingness)
• We will drive you to the airport. (willingness)
• Let’s see – I’ll have the blue one. (decision)
• I think I will order a Special Chow Mein tonight. (choice)

Should can express expectations about future events:

• The work should be finished by noon.
• This medicine should help with your headache.

Hypothetical Situations

Would can be used to express hypothetical situations:

• What would you do if you were me?
• Where would you go on your dream holiday?
• If we had left earlier, we would have avoided the traffic.
• If I won the lottery, I’d quit my job.

Could shows hypothetical ability and situations to express what might be possible:

• We could visit the Louvre if it’s not too crowded.
• We could have a barbecue later if it stops raining.
• You could save money if you cooked at home more.
• You could teach English abroad if you got a TEFL qualification.

Might can express hypothetical possibility:

• If the weather improves, we might have a BBQ.
• He might have taken the wrong train.
• As you like your history, you might find this documentary interesting.

Past Habits

We use would to express past habits:

• They would visit their grandparents every Christmas.
• We would stay up late watching movies on weekends.
• He would always arrive early for work.

Preferences

Finally, would can express what someone prefers or would rather do:

• I would rather take the stairs than wait for this elevator.
• Would you prefer to meet on Monday or Tuesday?
• She would much rather work from home than face the daily commute into London.

Negatives with Modal Verbs

Forming negatives with modal verbs follows a simple pattern. We typically place not directly after the modal verb.

For example:

Positive Sentence		Negative Sentence
Subject | Modal | Base Verb You | should | go.	➝	Subject | Modal | Negative | Base Verb You | should | not | go.

More examples:

• You should not drive when you’re tired. (or shouldn’t)
• I won’t be home until late tonight. (or will not)
• I’m sorry, I can’t speak Spanish. (or cannot)
• He couldn’t understand the instructions. (or could not)
• You must not enter this area without personal protective equipment (PPE). (or mustn’t)

Note: The modal verb can combines with not to form the single word cannot. This form is typically more emphatic and formal than the contraction can’t. Compare ‘I cannot deal with this situation right now.’ (formal and strong-sounding) with ‘I can’t come today.’ (informal and more casual-sounding).

---

While not is usually placed directly after the modal verb, adverbs (e.g., probably, definitely, potentially, absolutely, certainly, clearly) can sometimes come between the modal and not.

For instance:

• You should definitely not drive under the influence.
• I will probably not attend their wedding.
• We will likely not finish before the deadline.

Note: With contractions, the adverb usually goes before the modal verb (e.g., You definitely shouldn’t drive under the influence).

Questions with Modal Verbs

Creating questions with modal verbs typically involves moving the modal verb to the beginning of the sentence.

For example:

Positive Sentence		Question Sentence
Subject | Modal | Base Verb | Rest of Sentence We | can | meet | later.	➝	Modal | Subject | Base Verb | Rest of Sentence Can | we | meet | later?

More examples:

• You will be there tonight. → Will you be there tonight?
• I should call the doctor. → Should I call the doctor?
• You would like some tea. → Would you like some tea?
• You could pass the salt. → Could you pass the salt?

Question Words

We can combine question words (e.g., what, where, when, why, how) with modal verbs. The question word (or phrase) comes first, followed by the modal verb.

The word order is: Question Word (or Question Phrase) + Modal + Subject + Base Verb

• What can I do to help?
• Where should we meet?
• When will you arrive?
• Why must we wait?
• How could this happen?
• Which movie should we watch?
• How much will it cost?
• How often should you exercise?

Question Tags

Modal verbs can be used in question tags to check information or ask for agreement.

• If the main statement is positive, the tag is negative.
• If the main statement is negative, the tag is positive.

– Positive Statements > Negative Question Tags:

• You can drive, can’t you?
• She will love this restaurant, won’t she?
• We should book a table for tonight, shouldn’t we?
• You would like another piece of cake, wouldn’t you?
• He could help us move this weekend, couldn’t he?

– Negative Statements > Positive Question Tags:

• You can’t speak German by any chance, can you?
• He shouldn’t be driving without his glasses, should he?
• She can’t be serious about quitting, can she?
• They won’t mind if we’re a few minutes late, will they?
• We shouldn’t leave without saying goodbye, should we?

Semi-Modal Verbs

Semi-modal verbs express similar meanings to modal verbs – things like ability, necessity, obligation, and past habits. However, they behave differently grammatically.

Unlike pure modal verbs, semi-modals can change form to show different tenses and often use do/does/did in questions and negatives.

The main semi-modal verbs are used to, need to, have to, be able to, and be supposed to.

Used To

Used to describes past habits or conditions that no longer exist. While both used to and would work for past habits, only used to can describe past conditions that are no longer true.

For past habits, both work similarly:

• I used to play tennis every weekend when I was in school. (past habit)
• I would play tennis every weekend when I was in school. (past habit)

However, for past conditions, only used to works:

✅ – This used to be a quiet neighbourhood. (past condition – no longer true according to speaker)
❌ – This would be a quiet neighbourhood. (would doesn’t work for past conditions)

Need To

Need to expresses necessity and obligation, similar to must but it’s more common in everyday speech.

• I need to finish my essay by tomorrow. (present)
• I needed to go to the shop after work. (past)
• We’ll need to leave early tomorrow. (future)
• You don’t need to bring anything to the party. We have everything ready. (present negative)
• Do you need to charge your phone before we leave? (present question)

Have To

Have to expresses obligation or necessity, similar to must. It’s typically used when the obligation involves outside circumstances, rules, or other people’s expectations.

• I have to renew my passport before the trip. (present)
• We had to switch flights due to the delay. (past)
• We’ll have to be there by 6 pm tomorrow at the latest. (future)
• You don’t have to come if you’re busy. (present negative)
• Did you have to wait long for the bus from the airport? (past question)

Be Able To

Be able to expresses ability, similar to can. It’s particularly useful because it works across more tenses and contexts than can.

• I am able to help you now that I’ve finished work. (present)
• She was able to negotiate a pay rise. (past)
• I will be able to drive after I pass my test. (future)
• I have been able to work from home since the pandemic. (present perfect)
• They weren’t able to reach the top of the mountain. (past negative)
• Will you be able to cover my shift tomorrow? (future question)

Be Supposed To

Be supposed to expresses expectation or obligation, similar to should.

• She is supposed to take her medication with food. (present)
• I was supposed to go fishing today, but the weather is too bad. (past)
• You aren’t supposed to park here. (present negative)
• Am I supposed to dress up for the party next week? (present question)
• Next week, I am supposed to start my new role in a different department. (Future – be supposed to typically uses present forms when talking about future events because it doesn’t work well with will.)

---

• ShareCopied to clipboard

Next: Infinitives & Gerunds >