EnglishCBSE Class 10 · Grammar

Modals for CBSE Class 10 English Grammar

Updated 14 October 2026 · Fact-checked

Modals are helping verbs such as can, could, may, might, must, should, ought to, will, would and shall. They show ability, permission, possibility, necessity, advice or obligation. In the CBSE Class 10 paper, modals come in Question 3 as one-mark gap-filling, editing or transformation items, where one word decides the mark.

Find the clue phrase in the sentence first, then pick its modal and follow it with the base form of the verb.

Illustration drawn for QuestionBuddy.

Understand Modals

A modal verb is a helping verb that adds a speaker's attitude to the main verb: whether something is possible, allowed, necessary, advisable or able to happen. Compare 'He goes to the gym' (a plain fact) with 'He must go to the gym' (necessity), 'He may go' (possibility or permission), 'He should go' (advice) and 'He can go' (ability or permission). Modals have three fixed habits. First, they take the base form of the verb after them: 'She can sing', never 'She can sings' or 'She can to sing' (ought to is the one modal that keeps 'to'). Second, they do not change for the subject: 'he can', 'they can'. Third, they make questions and negatives without 'do': 'Can you swim?', 'You must not shout.' For the past, some modals have a past form (can becomes could, will becomes would, may becomes might, shall becomes should in reported speech), and others use 'have + past participle': 'He must have missed the bus' (a strong guess about the past), 'You should have told me' (advice that came too late). In the board paper the context sentence always contains a clue: a word like 'perhaps' points to may or might, 'it is compulsory' points to must, 'my advice' points to should, and 'when I was five' points to could. Reading for that clue is the whole skill.

Modals: rules and format

1
Ability: can (present), could (past), will be able to (future)
Riya can solve this sum in a minute. As a child, she could swim across the river. After the course, she will be able to drive.
Use 'was able to' for one successful achievement in the past: 'The fire spread, but everyone was able to escape.'
2
Permission: may (formal), can (informal), could (polite request)
May I come in, sir? Can I borrow your pen? Could you open the window, please?
In a formal letter or notice, prefer 'may'.
3
Possibility: may (fair chance), might (smaller chance), could (possible)
It may rain this evening. He might come, but I doubt it.
Clue words: perhaps, possibly, there is a chance.
4
Necessity or obligation: must (from the speaker), have to (from outside)
I must finish this today. Students have to wear the uniform on Mondays.
Must has no past form: use 'had to': 'Yesterday I had to walk home.'
5
Prohibition: must not; lack of necessity: need not / do not have to
You must not use phones in the exam hall. You need not bring lunch; it will be served.
'Must not' = it is forbidden. 'Need not' = it is not necessary. They mean different things.
6
Advice or duty: should, ought to
You should drink more water. We ought to respect our elders.
Ought to keeps 'to'; should does not.
7
Strong deduction: must (sure it is true), can't (sure it is not true)
The lights are off; they must be asleep. That can't be Ravi; he is in Delhi.
For the past: must have + past participle, can't have + past participle.
8
Future, offers and promises: will, shall
I will help you with the project. Shall I carry your bag?
'Shall I / Shall we' is used for offers and suggestions.
9
Polite requests and past habits: would
Would you mind waiting? When we lived in Shimla, we would walk to school every day.
'Would' for a repeated past action, 'used to' for a past state or habit.
10
Past regret or criticism: should have / ought to have + past participle
You should have revised the last chapter.
Shows that the right action did not happen.

How to answer Modals questions

Use this four-step check for every modal gap or error in Question 3.

1Read the whole sentence, and the sentence before and after it if the item is part of a passage.
2Find the clue: ability, permission, possibility, necessity, prohibition, advice, deduction or a polite request.
3Check the time: present, past or future. If the sense is past, use could, had to, might have, must have or should have.
4Check the form after the modal: base verb (or have + past participle). Never add -s, -ed or 'to' (except ought to).

Modals in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Must not versus need not

Suppose your class teacher writes two notices for a school trip: 'Students must not carry mobile phones' and 'Students need not bring lunch.' Your friend Aarav says both notices forbid something.

Explain to Aarav, with the grammar rule, what each notice means and what he should pack.

Try it first, then show the solutionSolution

'Must not' expresses prohibition: carrying a phone is forbidden.
'Need not' expresses lack of necessity: bringing lunch is optional, not forbidden.
So Aarav leaves his phone at home and may bring lunch if he wants.

Answer: 'Must not' means something is forbidden, so Aarav must leave his phone at home. 'Need not' means it is not necessary, so lunch is optional; he may still carry it if he likes.

Memory hook: Must not = a locked door; need not = an open door you don't have to use.

Tricks to remember Modals

Short memory aids. Say each one aloud once, then use it on a question the same day.

Clue word to modal
perhaps → may/might; compulsory → must/have to; my advice → should; was able as a child → could; I'm sure it's true → must; I'm sure it's false → can't.
Use it when: Underline the clue word in the item before choosing the modal.
Modal + V1
Every modal is followed by V1 (base form): can go, must go, should go. Only 'ought' needs 'to'.
Use it when: In editing items, an -s or -ed after a modal is almost always the error.
Past of guesses: modal + have + V3
must have gone (sure), might have gone (unsure), can't have gone (sure not), should have gone (regret).
Use it when: When the time clue is past and the sense is a guess or regret.

Modals: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Choosing the modal from the clue · 1 mark · MCQBoard level

Complete with the correct option: 'The doctor said that my grandfather ______ avoid fried food, as it was harmful for his heart.'
(a) can
(b) must
(c) might
(d) would

Try it first, then show the solutionSolution

Clue: 'as it was harmful for his heart' shows a strong necessity, not ability or possibility.
Necessity is expressed by must.
In reported speech after 'said', 'must' stays 'must'.

Answer: (b) must. The doctor is stating a necessity for health, and 'must' keeps its form in reported speech.

Example 2: Editing: modal followed by the wrong form · 1 mark · Short answerHarder board level

Identify the error and give the correction: 'Visitors may parks their vehicles only in the marked area.'

Try it first, then show the solutionSolution

A modal is always followed by the base form of the verb.
'parks' carries an -s, which is wrong after 'may'.
Correct form: 'park'.

Answer: Error: parks. Correction: park ('Visitors may park their vehicles only in the marked area.')

Example 3: Past necessity · 1 mark · MCQHarder board level

Complete the sentence: 'The bridge was closed, so we ______ take a longer route to the station yesterday.'
(a) must
(b) had to
(c) should
(d) may

Try it first, then show the solutionSolution

Time clue: 'yesterday' and 'was closed' are past.
The necessity came from outside (the closed bridge).
'Must' has no past form; the past of necessity is 'had to'.

Answer: (b) had to. The sentence is in the past and the necessity was caused by the closed bridge; 'must' cannot show past necessity.

Example 4: Deduction about the past · 1 mark · MCQHarder board level

Read the situation and complete the sentence with a modal: 'Meera's bag is not on her desk and her bicycle is missing from the stand. She ______ left for home already.'
(a) must have
(b) should have
(c) need have
(d) would have

Try it first, then show the solutionSolution

The speaker is making a confident guess from evidence (bag and bicycle gone).
A confident guess about the past uses 'must have + past participle'.
'Should have' would mean regret or criticism, which does not fit.

Answer: (a) must have. Two pieces of evidence make the speaker sure, and the action is in the past, so 'must have left'.

Example 5: Two modals in one passage · 1 mark · MCQHOTS / competency

Fill in the two blanks with suitable modals: 'In the exam hall you (i) ______ not talk to anyone, but you (ii) ______ ask the invigilator for an extra sheet if you need one.'
(a) (i) need, (ii) must
(b) (i) must, (ii) may
(c) (i) may, (ii) must
(d) (i) should, (ii) need

Try it first, then show the solutionSolution

Blank (i): talking in the exam hall is forbidden, so 'must not' (prohibition).
Blank (ii): asking for a sheet is allowed, so 'may' (permission).
Option (b) is the only pair that gives prohibition and then permission.

Answer: (b) (i) must, (ii) may. 'Must not' forbids talking; 'may' gives permission to ask for a sheet.

Example 6: Regret in the past · 1 mark · Short answerHOTS / competency

Rewrite as one sentence using a modal of regret: 'Kabir did not revise the map work. He lost five marks.'

Try it first, then show the solutionSolution

The right action (revising) did not happen in the past.
Past regret or criticism uses 'should have + past participle'.
Join the result with 'or he would not have lost five marks'.

Answer: Kabir should have revised the map work; then he would not have lost five marks.

Where students lose marks in Modals

The slips examiners see most often, and what to write instead.

Mistake: Adding -s, -ed or 'to' after a modal
Modals are always followed by the base form (ought to is the only exception).
Wrong working
He can speaks three languages.
Right working
He can speak three languages.
Do this: After you choose a modal, read the next word and make sure it is V1.
Usually costs: 1 mark per item
Mistake: Confusing 'must not' with 'need not'
'Must not' forbids; 'need not' says something is unnecessary.
Wrong working
You must not come early; the shop opens at 10. (meant: it is not necessary)
Right working
You need not come early; the shop opens at 10.
Do this: Ask: is it forbidden or just unnecessary?
Usually costs: 1 mark
Mistake: Using 'must' for a past obligation
'Must' has no past form; past necessity is 'had to'.
Wrong working
Yesterday I must stay at home.
Right working
Yesterday I had to stay at home.
Do this: If the time clue is past, use 'had to'.
Usually costs: 1 mark
Mistake: Ignoring the clue sentence in a passage
The modal depends on the meaning in context, and the clue is often in the next sentence.
Do this: Read the full passage once before filling any gap.
Usually costs: 1-2 marks across the question
Mistake: Using 'should have' for a confident guess
'Should have' shows regret; a confident guess about the past is 'must have'.
Wrong working
Her lights are off; she should have gone to bed.
Right working
Her lights are off; she must have gone to bed.
Do this: Guess = must have; regret = should have.
Usually costs: 1 mark

Exam tips

Question 3 asks you to attempt any ten of twelve items: do the items you are sure of first, then return to the doubtful ones.
In an editing item, copy the error word and the correction exactly as asked; do not rewrite the whole sentence unless asked.
Look for time clues (yesterday, as a child, next week) before choosing between can/could, must/had to and will/would.
When two options seem right, choose the one that matches the speaker's attitude in the context, not the one that only sounds natural.
Write the modal and the verb with correct spelling; a misspelt correct answer can lose the mark.

Practice questions on Modals

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
Choose the correct option: '______ I use your calculator for a minute?' (a polite request to a teacher)
(a) Must
(b) May
(c) Should
(d) Would
Hint
Asking for permission formally.
Answer
(b) May. 'May I...' asks for permission politely; it is the right choice when speaking to a teacher.
Q2 · 1 mark · MCQBoard level
Choose the correct option: 'When she was only six, my cousin Priya ______ run faster than all the boys in her village.'
(a) can
(b) could
(c) must
(d) should
Hint
Ability in the past.
Answer
(b) could. 'When she was only six' is a past time clue, and the sentence is about ability.
Q3 · 1 mark · Short answerHarder board level
Identify the error and correct it: 'You ought follow the traffic rules even when no policeman is around.'
Hint
Which modal is always followed by 'to'?
Answer
Error: ought follow. Correction: ought to follow. 'Ought' is the one modal that needs 'to' before the verb.
Q4 · 1 mark · MCQHarder board level
Complete with a modal: 'That ______ be Ritu at the door; she left for Pune this morning.'
(a) must
(b) can't
(c) may
(d) should
Hint
The speaker is sure it is NOT Ritu.
Answer
(b) can't. The speaker has evidence (she left for Pune) and is sure it is not her; 'can't' expresses a negative deduction.
Q5 · 1 mark · MCQHarder board level
Complete with the correct option: 'You ______ water the plants today; it rained heavily last night.'
(a) must not
(b) need not
(c) cannot
(d) ought
Hint
Is watering forbidden, or simply unnecessary?
Answer
(b) need not. Watering is not necessary because of the rain; it is not forbidden, so 'must not' is wrong.
Q6 · 1 mark · Short answerHarder board level
Identify the error and correct it: 'The principal said that the students must had to stay back for the rehearsal.'
Hint
Can a modal be followed by a past form such as 'had'?
Answer
Error: must had to. Correction: had to (or must). A modal is never followed by a past form like 'had'; in this reported sentence 'had to' alone (or 'must') gives the necessity.
Q7 · 1 mark · MCQHOTS / competency
Fill in the blanks with the correct set of modals: 'If you (i) ______ not finish the project today, you (ii) ______ ask for an extension, but you (iii) ______ submit it by Friday.'
(a) (i) can, (ii) may, (iii) must
(b) (i) must, (ii) can, (iii) may
(c) (i) may, (ii) must, (iii) can
(d) (i) should, (ii) must, (iii) need
Hint
Ability, then permission, then a firm deadline.
Answer
(a) (i) can, (ii) may, (iii) must. 'Cannot finish' is lack of ability, 'may ask' is permission, and 'must submit' is a firm obligation.
Q8 · 1 mark · Short answerHOTS / competency
Rewrite using a modal so that the meaning stays the same: 'It is possible that the train is late because of the fog.'
Hint
Possibility in the present.
Answer
The train may (or might) be late because of the fog. 'May/might + be' expresses present possibility.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.What form of the verb follows a modal?Show answer
The base form (V1): can go, must eat. Only 'ought' takes 'to'.
2.What is the past form of 'must' for necessity?Show answer
had to.
3.Which modal shows a confident negative deduction?Show answer
can't (cannot): 'That can't be true.'
4.What is the difference between 'must not' and 'need not'?Show answer
'Must not' = prohibited; 'need not' = not necessary.
5.Which modal is used for offers like 'Shall I help?'Show answer
shall (with I or we).

Modals: frequently asked questions

Are 'have to' and 'need to' modals?

They are semi-modals: they behave like ordinary verbs (has to, had to, do not need to) but express necessity like modals. The CBSE syllabus tests them along with the main modals in context.

Can two modals be used together?

No. 'Must can' or 'will can' is wrong. Use a modal with a semi-modal instead: 'will be able to', 'may have to'.

Is 'could' only the past of 'can'?

No. 'Could' is also used for polite requests ('Could you help me?') and for possibility ('It could rain').

How many modal questions come in the board paper?

There is no fixed number. Question 3 has twelve grammar items across determiners, tenses, modals, subject-verb concord and reported speech; you answer any ten, each worth one mark.

What is the difference between 'should' and 'must'?

'Should' gives advice or a duty that is recommended; 'must' expresses a strong necessity or rule. 'You should exercise daily' (advice); 'You must wear a helmet' (rule).