❖ Unit 2 ❖ Humour ❖ Grammar ❖

Modal Verbs

Modals (can, could, must, should, may, might, will, would, need, ought to) express ability, possibility, obligation, advice, permission, certainty and deduction. Mastering modals is essential for the National Exam's language section and for natural English.

Three golden rules of modals

Modals are followed by a bare infinitive (verb without "to"): She can swim. NOT She can to swim.
Modals have no -s in the third person: He must go. NOT He musts go.
To form a question, invert the modal and the subject: Can you help me? NOT Do you can help me?

Modals by function

① Ability

can / could / be able to + bare infinitive

I can speak three languages. (present)

She could swim when she was five. (past)

② Permission

can / could / may + bare infinitive

Can I borrow your book? (informal)

May I come in? (formal)

③ Obligation / Necessity

must / have to + bare infinitive

Students must arrive on time. (strong rule)

I have to work tomorrow. (external obligation)

④ Absence of obligation

needn't / don't have to + bare infinitive

You needn't come early; the meeting is at 10.

I don't have to work on Sundays.

⑤ Prohibition

mustn't + bare infinitive

You mustn't smoke in the hospital.

Children mustn't watch horror films.

⑥ Advice

should / ought to / had better + bare infinitive

You should revise more.

You had better see a doctor.

⑦ Possibility / Probability

may / might / could + bare infinitive

It may rain tomorrow.

The baby might wake up — please be quiet.

⑧ Certainty / Logical deduction

must (positive) / can't (negative) + bare infinitive

The film must be interesting — everyone wants to see it.

He can't be Tim; Tim is in Turkey.

Past modals — modal + have + past participle

To talk about the past, modals take the form: modal + have + V3 (past participle).

must have + V3

= Certainty about something in the past.

The children ate all the food. They must have been very hungry.

should have + V3

= Regret about a past action that didn't happen.

Nora got a bad mark. She should have revised her lessons well.

could have + V3

= A past possibility that didn't happen.

Why didn't you come? You could have enjoyed the party.

might have + V3

= A past possibility (uncertain).

Mr. Robert didn't come. He might have forgotten about the meeting.

needn't have + V3

= An unnecessary past action.

You needn't have bought all this food. There aren't many guests.

can't have + V3

= Impossibility in the past.

Sami can't have cheated; he is honest and hard-working.

Practice 1 — Choose the right modal

Fill in the gaps with the correct word from the list

I have an exam tomorrow. So, I must study hard tonight. (obligation)
Nora got a bad mark in the exam last week. She should have revised her lessons well.
Last night I was alone at home, so I had to prepare dinner myself. (past obligation)
They must have arrived because they took the train two days ago.
Please keep quiet! The baby might wake up.
I can't find my keys. Maybe I lost them.
Everybody wants to see the new film. It must be very interesting. (deduction)
"You don't have to take notes. I'll give a copy of the whole lesson," a teacher told his students.

Practice 2 — More modals

Fill in the gaps

Why didn't you come to the party? You could have enjoyed it very much.
The children ate all the food. They must have been very hungry.
Could you help me with maths, please?
The woman is extremely rich. She needn't work.
Children mustn't watch horror films. They are dangerous.
You don't have to give me back the money immediately. Take your time.
Mr. Robert didn't come to the meeting yesterday. He might have forgotten about it.

Items from past National Exams

Choose the right modal

You needn't carry this suitcase, the porter will take care of it.
You needn't buy a ticket for the match. I've got invitations for both of us.
Sami can't have cheated in the exam; he is honest and hard-working.
Rachid can't find his mobile. He might have left it in his father's car.
Rich: He can't be Tim. He's on holiday in Turkey.
You needn't go to the university to register. You can send your application by email.
My parents may travel at the weekend if the weather is nice.
You needn't have bought all this food. There aren't many guests.
We must be at the bus stop by 8:00 if we don't want to miss the bus.
I can't find my keys. I must have left them at home.
"You mustn't break the law." The policeman told the motorist.
My friend Kamal looks happy and satisfied today. He must have done well on the test.

❖ Key Takeaways ❖

① Modal + bare infinitive

Never "to" after a modal. Never -s in 3rd person.

② Each modal has a function

Memorise by function: ability (can), advice (should), obligation (must), deduction (must/can't), possibility (may/might), permission (can/may).

③ Past modals = modal + have + V3

should have (regret) · must have (past certainty) · could have (missed opportunity) · might have (past possibility) · needn't have (unnecessary action).

❖ Exam tip

Modals appear in almost every National Exam paper, typically in the multiple choice exercise (2-4 points). Common traps: must vs have to, needn't vs mustn't, could vs could have. Always read the context: is it advice, obligation, regret, or deduction?