Modals – Rules & Examples

What are Modals?

Modals are helping verbs that express ideas such as ability, possibility, permission, obligation, necessity, advice, request, and willingness.

Common modals include:
can, could, may, might, must, shall, should, will, would, ought to

Examples

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• I can swim.
• You should work hard.
• We must obey the rules.
• May I come in?
• It might rain today.

Basic Rule of Modals

A modal is followed by the base form (V1) of the main verb.

Structure
Subject + Modal + V1 + …

Examples

• She can speak English.
• He should study regularly.
• They must follow the rules.
• We will attend the meeting.

1. Can

Can is used to express:

• Ability
• Permission
• Possibility

Ability

• I can solve this problem.
• She can speak English fluently.

Permission

• Can I use your pen?
• Can we go outside?

Possibility

• It can be very cold in December.

2. Could

Could is commonly used for:

• Ability in the past
• Polite requests
• Possibility

Past Ability

• When I was young, I could run very fast.
• She could swim when she was six.

Polite Request

• Could you help me?
• Could you lend me your book?

Possibility

• It could rain tonight.
• This could be the reason for the problem.

3. May

May is used to express:

• Permission
• Possibility
• Wish or prayer

Permission

• May I come in?
• May I use your phone?

Possibility

• It may rain today.
• She may arrive late.

Wish / Prayer

• May you succeed in life.
• May God bless you.

4. Might

Might generally expresses a weaker possibility.

Examples

• It might rain tonight.
• He might come to the party.
• She might be busy.

Compare

• It may rain. → possible
• It might rain. → possible, but less certain

5. Must

Must expresses:

• Strong obligation
• Necessity
• Strong conclusion

Obligation / Necessity

• Students must follow the school rules.
• You must complete your homework.

Strong Conclusion

• He must be tired after the journey.
• She must be at home; her car is outside.

Important

Must not / mustn’t means prohibition.

• You must not enter this room.
• Students mustn’t use mobile phones during the examination.

6. Should

Should is mainly used for:

• Advice
• Duty
• Expected action
• Possibility

Advice

• You should work hard.
• We should respect our elders.

Duty

• We should help those in need.

Expected Action

• The train should arrive soon.
• He should be home by now.

7. Ought to

Ought to is used to express:

• Duty
• Advice
• Moral obligation
• Expected action

Examples

• We ought to respect our parents.
• You ought to help the poor.
• Students ought to obey their teachers.

Important

Unlike most modals, ought is followed by to + V1.

✔ You ought to work hard.

❌ You ought work hard.

8. Will

Will is used to express:

• Future action
• Willingness
• Promise
• Determination

Future Action

• I will visit Delhi tomorrow.
• She will complete the work soon.

Willingness

• I will help you.
• He will carry the bag.

Promise

• I will never forget your help.
• We will support you.

9. Would

Would is commonly used for:

• Polite requests
• Polite offers/invitations
• Preference
• Imaginary or conditional situations

Polite Request

• Would you help me?
• Would you please close the door?

Offer / Invitation

• Would you like some tea?
• Would you like to join us?

Preference

• I would rather stay at home.

10. Shall

Shall is used mainly for:

• Suggestions
• Offers
• Asking for instructions or decisions

Suggestions

• Shall we start the meeting?
• Shall we go for a walk?

Offer

• Shall I help you?
• Shall I open the window?

Important Difference Between Modals

Can vs Could

Can → present ability / permission

• I can swim.

Could → past ability / polite request / possibility

• I could swim when I was five.
• Could you help me?

May vs Might

Both can express possibility.

May → possibility

• She may come today.

Might → weaker possibility

• She might come today.

Must vs Should

Must → strong obligation / necessity

• You must wear a helmet.

Should → advice / recommendation

• You should exercise regularly.

Will vs Would

Will → future / willingness

• I will help you.

Would → polite request / preference / conditional use

• Would you help me?

Negative Forms of Modals

To make a modal negative, generally use not after the modal.

Examples

• can → cannot / can’t
• could → could not / couldn’t
• may → may not
• might → might not
• must → must not / mustn’t
• should → should not / shouldn’t
• will → will not / won’t
• would → would not / wouldn’t
• shall → shall not / shan’t

Examples

• You cannot enter the room.
• He should not waste his time.
• She may not attend the meeting.
• We must not break the rules.

Modals in Questions

The modal generally comes before the subject.

Structure

Modal + Subject + V1 + …?

Examples

• Can you help me?
• May I come in?
• Could you explain this?
• Should we start now?
• Will you attend the meeting?

Modals with Passive Voice

A modal can be followed by be + past participle (V3) in passive constructions.

Structure

Subject + Modal + be + V3

Examples

• The work must be completed today.
• The rules should be followed.
• The problem can be solved easily.
• The letter may be sent tomorrow.

Modals with Perfect Forms

For actions that happened in the past, modal + have + V3 may be used.

Structure

Subject + Modal + have + V3

Examples

• He must have forgotten the meeting.
• She may have missed the bus.
• They could have won the match.
• You should have informed me earlier.

Common Errors

Error 1

❌ He can speaks English.

✔ He can speak English.

Rule: Modal + V1.

Error 2

❌ You should to work hard.

✔ You should work hard.

Error 3

❌ He must to obey the rules.

✔ He must obey the rules.

Error 4

❌ She may comes tomorrow.

✔ She may come tomorrow.

Error 5

❌ You ought work hard.

✔ You ought to work hard.

Rule: Ought + to + V1.

Quick Revision Table

Exam Tips for Class 10

1. After most modals, use the base form (V1) of the verb.
2. Do not use to after can, could, may, might, must, should, will, would, or shall.
3. Ought to is an important exception: use ought to + V1.
4. Choose the modal according to the meaning and context of the sentence.
5. Pay special attention to the difference between must, should, may, might, can, and could.
6. In fill-in-the-blank questions, read the complete sentence before selecting the modal.

Quick Formula

Modal + V1

✔ She can dance.

✔ You should study.

✔ He must obey.

Ought to + V1

✔ You ought to respect your parents.