REET L1+L2 · English (Language I/II)

Modals (Modal Auxiliaries): can, may, must, shall, ought to — Usage and Rules

This page covers every important modal auxiliary — can, could, may, might, shall, should, will, would, must, ought to, need, dare, and used to — along with the meanings they carry (ability, permission, obligation, threat, and more), the rules that govern them, and the mistakes aspirants commonly make. REET 2024 carried 6 questions on Modals, almost all of them fill-in-the-blank items.

6 questions in REET 2024
Class 6–10 grammar level
9-minute read

Verified 17 September 2026 · Source: Modal verbs and modality — English Grammar Today, Cambridge Dictionary

How REET asks this topic

All 6 Modals questions in REET 2024 were fill-in-the-blank, and several even named the meaning in brackets: 'You ___ pay your debts' (moral duty → ought to), 'Your sister is very serious, you ___ take her to a doctor (obligation)' → must, 'You ___ punished for this (Threat)' → shall be, a rule printed on an office notice → must, ability in a past-tense sentence → could, and 'I don't think I ___ be able to go' → shall. In short, the exam tests whether you can read the 'meaning' behind each modal and match it to the tense of the sentence. Options often pair up close look-alikes like must/should and may/might, so the fine differences between them have to be memorised precisely.

What Modals Are, and Their Rules

Modal auxiliaries are helping verbs that attach to a main verb to express the speaker's stance — ability, permission, possibility, obligation, duty, advice, threat, wish, and more. The main modals are: can, could, may, might, shall, should, will, would, must, ought to; need, dare and used to are usually called semi-modals.

The core rules: (1) A modal is always followed by the base form of the verb (V1) — He can swim, never He can swims. (2) No -s is added even with third-person singular subjects — She must go. (3) 'ought to' and 'used to' take 'to'; no other modal does — You must to go is wrong. (4) Two modals never stack together — will can is wrong; you say will be able to instead. (5) Modals have no -ing or V3 form. (6) Questions and negatives never need do/does/did — Can you help? / You must not smoke.

Must has no separate past form; past obligation is expressed with had to — I had to walk home. Similarly, future ability for can is expressed with will/shall be able to, exactly as in the REET 2024 question: I don't think I shall be able to go there.

Every modal and its meaning

Modal	Meaning	Example
can	Ability, informal permission	She can speak three languages. / You can go now.
could	Past ability, polite request, lower possibility	He could not catch the thief. / Could you open the window?
may	Formal permission, possibility, wish	May I come in, sir? / It may rain today. / May you live long!
might	Lower possibility, past form of may (in reported speech)	He might come, but I am not sure.
shall	Future with I/We; order, promise or threat with You/He/They	We shall overcome. / You shall be punished for this. (threat)
should	Advice, duty	You should see a doctor. / We should respect elders.
will	Future with You/He/They; determination or promise with I/We	I will help you. (promise)
would	Polite request, past habit, wish	Would you help me? / He would walk every morning.
must	Obligation/necessity, strong inference	Staff must be at their desks by 9:00 am. / He must be tired.
ought to	Moral obligation	You ought to pay your debts. / We ought to help the poor.
need	Necessity — as a modal, mostly in negatives/questions	You need not worry. / Need I go?
dare	Courage to do something — as a modal, mostly in negatives/questions	How dare you speak like that? / He dare not oppose.
used to	A past habit that no longer holds	I used to play cricket in my childhood.

Fine differences between look-alike modals (the exam's favourite trap)

Pair	Difference	Example
must vs should	must = a compulsory rule/obligation; should = advice, with no penalty for not following it	You must wear a helmet (rule). You should eat fruits (advice).
should vs ought to	Both express duty; ought to leans more towards a moral/social obligation	You ought to obey your parents.
can vs may	can = ability; may = formal permission or possibility	I can lift this box. / May I use your pen?
may vs might	might suggests a lower possibility than may	It may rain. / It might rain (less likely).
must not vs need not	must not = prohibition; need not = no necessity, but not forbidden either	You must not park here. / You need not come tomorrow.
can vs could	could = the past of can (ability) or a more polite request	When I was five, I could swim. / Could I leave early?

Modal + have + V3: Past-Tense Meanings

When you need to express an inference, regret, or possibility about something in the past, you use modal + have + V3. must have + V3 = a strong inference about the past (The road is wet; it must have rained). should have / ought to have + V3 = regret or criticism about a duty that was not fulfilled (You should have told me earlier). may have / might have + V3 = past possibility (He may have missed the bus). could have + V3 = the ability existed, but the thing didn't happen (You could have won the match).

A quick way to spot the right modal from meaning: a rule, a notice-board instruction, or a law → must; a moral point (repaying a debt, caring for elders) → ought to; advice → should; a past-tense sentence about ability → could; a threat/order/promise aimed at a second or third person → shall. All six REET 2024 questions can be solved with exactly these cues.

How to Teach This to Children

Classes 4–5: The Can/Can't Chart

Put up pictures of animals and ask — 'Can a fish fly?' Children answer 'No, it can't. A fish can swim.' This is how the ability-sense of can is picked up naturally.

Classes 6–8: Class Rules

Work with the class to build a 'Class Rules' chart — 'We must come on time. We should keep our desks clean. We must not shout.' This makes the difference between must, should and must not clear in a real context.

Role play

Run a doctor–patient dialogue: 'You should drink more water. You must take this medicine twice a day.' And a polite request at a shop: 'Could you show me that bag?'

Teaching aids

A substitution table (Subject | Modal | V1), pictures of notice-boards (No Parking, Keep Silence), and meaning-cards (ability, advice, permission).

Common misconceptions

Mistakes such as She can sings, He must to go, I will can; treating must and should as the same; and confusing need not with must not.

Assessment idea

Give meaning-based fill-in-the-blanks — write (advice), (permission), (moral duty) in brackets after a sentence and have students fill in the right modal; then let them build two sentences of their own.

Memory trick / exam tip

Remember the meaning-formula: 'Rule = must, morality = ought to, advice = should, permission = may, ability = can (could in the past), threat/order (with You/He) = shall.' If a meaning is given in brackets, pick straight from this formula; and a modal is always followed by V1 — without 'to' (except ought to and used to).

Questions asked in REET 2024 (solved)

Question 73

You ________ pay your debts.

Awill
Bcan
Cought to
Dmay

Explanation

नैतिक कर्तव्य या दायित्व (moral obligation) व्यक्त करने के लिए ‘ought to’ का प्रयोग होता है — ऋण चुकाना नैतिक कर्तव्य है। ‘will’ भविष्य, ‘can’ क्षमता और ‘may’ अनुमति/संभावना बताते हैं।

Question 82

I don’t think I _________ be able to go there.

Acan
Bshall
Cmust
Dshould

Explanation

भविष्य काल में ‘I/We’ के साथ पारंपरिक व्याकरण में ‘shall’ का प्रयोग होता है और ‘be able to’ क्षमता का भविष्य रूप है: ‘I shall be able to go’। ‘can’ और ‘must’ के बाद ‘be able to’ नहीं आता, और ‘should’ सलाह/कर्तव्य बताता है।

Question 76

Your sister is very serious, you ________ take her to a doctor. (obligation)

Amay
Bshall
Cmust
Dshould

Explanation

बाध्यता या आवश्यक कर्तव्य (obligation/compulsion) व्यक्त करने के लिए modal 'must' प्रयुक्त होता है: 'you must take her to a doctor'। 'should' सलाह (advice) के लिए, 'may' अनुमति/संभावना के लिए होता है।

Question 77

You _______ punished for this. (Threat)

Ashould be
Bshall be
Cmust be
Dcould be

Explanation

दूसरे पुरुष (second person) या तीसरे पुरुष के साथ 'shall' का प्रयोग धमकी, आदेश या वचन (threat/command/promise) व्यक्त करता है। अतः 'You shall be punished for this.' धमकी का भाव देता है। 'should be' और 'must be' क्रमशः कर्तव्य और बाध्यता बताते हैं।

Question 62

He ran as fast as his legs allowed but he ___________ not catch the thief.

Acan
Bmay
Ccould
Dmight

Explanation

वाक्य Past tense में है ('He ran … allowed'), इसलिए क्षमता (ability) दिखाने के लिए 'can' का past रूप 'could' आएगा: 'but he could not catch the thief'. 'might' संभावना बताता है, क्षमता नहीं।

Question 65

‘Staff ___________ be at their desks by 9:00 am.’ This was written on the notice board of an office.

Ashould
Bmust
Cneed
Dwill

Explanation

कार्यालय के नोटिस बोर्ड पर लिखा नियम एक अनिवार्य दायित्व (obligation/compulsion) व्यक्त करता है, इसलिए 'must' सबसे उपयुक्त है: 'Staff must be at their desks by 9:00 am.' 'should' केवल सलाह देता है।

Practice questions

Question 1

Choose the grammatically correct sentence.

AShe can sings well.
BShe can sing well.
CShe can to sing well.
DShe cans sing well.

Explanation

A modal is always followed by the base form (V1) of the verb, with no 'to' and no '-s', so 'She can sing well.' is correct.

Question 2

______ I come in, sir? (formal permission)

AMay
BMust
CShould
DOught

Explanation

May is used to ask for formal permission. Must expresses obligation and should expresses advice; 'Ought' cannot appear here without 'to'.

Question 3

______ you live long! (wish)

ACan
BMay
CShall
DMust

Explanation

May is used at the start of a sentence to express a wish or blessing — May you live long!

Question 4

You ______ park your car here. It is a no-parking zone. (prohibition)

Aneed not
Bmust not
Cmay
Dcould

Explanation

must not is used for prohibition. need not only says something isn't necessary — it doesn't forbid it.

Question 5

The past form used to express obligation for ‘must’ is:

Amusted
Bhad to
Cmust had
Dought

Explanation

Must has no separate past form; past obligation is expressed with had to — I had to walk home yesterday.

Question 6

The ground is wet. It ______ rained last night. (strong deduction)

Amust have
Bshould have
Cought to have
Dneed have

Explanation

A strong inference about a past event is expressed with must have + V3. should have/ought to have express regret over an unfulfilled duty.

Question 7

I ______ play football every evening when I was a child, but now I don’t. (past habit)

Ause to
Bused to
Cam used to
Dwas use to

Explanation

A past habit that no longer continues is expressed with used to + V1.

Question 8

Which sentence expresses advice, not compulsion?

APassengers must wear seat belts.
BYou must not smoke in the hospital.
CYou should drink more water.
DStudents must carry their admit cards.

Explanation

should gives advice, while the other three sentences use must/must not to express a rule or compulsion.

Question 9

A teacher wants her Class 6 learners to understand the difference between ‘must’ and ‘should’. The most effective activity is:

AMaking them memorise a list of modals
BAsking them to frame class rules and friendly advice charts in groups
CDictating the definition of modals
DAsking them to copy sentences from the textbook

Explanation

Having groups frame class rules (must) and friendly-advice charts (should) helps children grasp the difference in a real context. Memorising a list or copying it does not build meaningful understanding.

Question 10

You ______ have told me about the test earlier; now I am not prepared. (regret/criticism)

Amight
Bshould
Ccan
Dmust

Explanation

should have + V3 expresses regret or criticism over something that ought to have been done but wasn't. must have expresses inference and might have expresses possibility.

Frequently Asked Questions

How many modals are there?+

The main modals are can, could, may, might, shall, should, will, would, must and ought to. need, dare and used to are called semi-modals.

What is the difference between Must and Should?+

Must expresses a compulsory obligation or rule (Staff must be at their desks by 9 am), while should expresses only advice or duty (You should exercise daily).

When is Ought to used?+

To express a moral or social duty, as in You ought to pay your debts. It is followed by V1, and 'to' is never dropped.

What is the past tense of Must?+

Must has no separate past form. Past obligation is expressed with had to; a past inference is expressed with must have + V3.

How many questions come from Modals in REET?+

REET 2024 carried 6 questions on Modals, all fill-in-the-blank, requiring modals like ought to, must, shall and could to be chosen by meaning.

Official Sources

Change Log

17 September 2026 — English page published — mirrors the fact-checked Hindi page, independently bilingual-accuracy checked

Modals (Modal Auxiliaries): can, may, must, shall, ought to — Usage and Rules

What Modals Are, and Their Rules

Every modal and its meaning

Fine differences between look-alike modals (the exam's favourite trap)

Modal + have + V3: Past-Tense Meanings

How to Teach This to Children

Questions asked in REET 2024 (solved)

Practice questions

Frequently Asked Questions

Read next

Conjunctions

Active & Passive Voice

REET Syllabus 2026

REET 2024 Solved Paper

Official Sources

Change Log