This document provides an overview of modal verbs in English including their different types and uses. There are several categories of modal verbs including: ability, permission/request, certainty/possibility, advice, obligation/lack of obligation, and prohibition. Each modal verb has specific meanings and uses depending on whether it is expressing ability, permission, certainty, possibility, advice, obligation, or prohibition. Modal verbs are also used with different verb tenses including the present, past, and perfect forms. Overall, modal verbs add nuance and meaning to statements, questions, permissions, obligations and more in the English language.

1. MODAL VERBSMODAL VERBS

2. 1. They are verbs like can, must, might, etc… which give
certain meanings to main verbs.
You smoke. / You shouldn’t smoke. / You mustn’t smoke.
2. They are followed by either:
– base form of the verb. I should tell him the truth.
– have + past participle form of the verb. I should have told
him the truth.
3. Structure:
(+) We should stay.
(-) We shouldn't stay.
(?) Should we stay?

3. 4. Types of Modal verbs:
ABILITY: can / could / *be able to
PERMISSION & REQUEST: can / could / may
CERTAINTY & LOCAL DEDUCTION: must / can’t
PROBABILITY & POSSIBILITY: can / could / may / might

4. ADVICE: should / ought to
OBLIGATION: must / *have to / need to
LACK OF OBLIGATION: don’t have to / don't need to / needn’t
PROHIBITION: mustn’t

5. ABILITY (can, could & *be able to)
1. Present: can
Two of my friends can play the guitar.
2. Past: could
When he was a child he could ski well.
3. Other tenses: be able to
- There was a fire and I was able to escape out (= I
managed to escape out) of the room. (specific situation in
the past)
- Next week they'll be able to vote. (future)
- We haven't been able to go on holiday this year. (present
perfect)

6. PERMISSION & REQUEST
(can, could & may)
Can you help me?
Could you send me your picture?
May I use your phone? (a bit more polite)

7. CERTAINTY / POSSIBILITY
(must , can’t & couldn't / could, may & might)
CERTAINTY POSSIBILITY
1. 100% SURE +
They must be an item. I’ve seen them
kissing.
(I totally believe this)
3. 80% - 30% % SURE + / -
They could / may / might be an item.
They’re good friends and…
They may not / might not be an item.
Some people say so ,but I’m not sure…
We can invite Jim to the party.
(Why not?)
We could / may invite Jim to the party.
(Not so sure…)
We might invite Jim to the party.
(Could be but I don’t think so…)
2. 100% SURE -
They can’t be an item. They don’t get
along.
( I don’t believe it)

8. ADVICE
(should / ought to)
You should / ought to study more for your exams.
You shouldn’t smoke.
* Ought to rarely seen in negatives or questions.

9. OBLIGATION / LACK OF OBLIGATION / PROHIBITION
OBLIGATION LACK OF OBLIGATION
HAVE TO // NEED TO DON’T HAVE TO /NEED TO // NEEDN’T
1. OBLIGATION which comes from sb else. It’s a
law or a rule and the speaker can’t change it.
In Britain you have to /need to buy a TV licence
every year.
She has to / needs to wear a school uniform.
You don’t have to / need to //needn’t order your
meal now.
She doesn’t have to / need to // needn’t cook
dinner tonight.
2. OBLIGATION with other verbal tenses:
I ‘ll have to pass those exams to go to university.
We had to leave early.
MUST PROHIBITION
3. OBLIGATION which comes from the speaker.
It isn’t a law or a rule.
I must call my dad tonight.
You must try some of this ice-cream.
(suggestion & recommendation)
MUSTN’T
You mustn’t drink and drive.

10. 5. Modal Perfects: They're used when referring to a past situation.
MUST
CAN’T
MAY / MIGHT / COULD + PERFECT INFINITIVE
SHOULD / OUGHT TO (have + past participle)
NEEDN’T

11. I'm sure that Danny must have felt disappointed when he didn't win the prize.
I'm sure that she can't have passed the exam, she didn't study at all.
He may / might have gone to the cinema but I'm not sure.
The situation is bad but it could have been worse. (it was possible but it didn't
happen)
He could have helped us, but he came too late.
She should have seen a doctor…She’s worse today.
Linda shouldn't have talked so much
Everything was ok. You needn’t have worried. (you worried but it was not
necessary)