Let’s review the meaning and use of modal verbs:

Can

 Ability: Can you play the piano?

 Theoretical possibility: Anyone can make a mistake.
 Permission: Can I leave early, please?
 Requests: Can you give me a hand?
 Offers: Can I help you out?

Can ’ t/ cannot

 Inability: I can't play the piano.

 Possibility: Can't you come any earlier? (= isn't it possible)
 Prohibition: You can't leave until I say so.
 Deduction: This bill can't be right.

Can ’ t have

 Deduction: She's gone to the wrong door, she can't have seen the sign.

Could

 Past ability: The shop had nothing that I could afford.

 Possibility: There could be trouble if the government tries to force this measure
through.
 Requests: Could you give me a hand?
 Asking for permission: Could I leave a bit early today?
 Permission in the past: When I was young, I could stay up late at weekends if I
promised to be good.
 Deduction: That could be John's car I can hear - he said he was coming.
 Idiomatic: You could at least tell me what they said. (= I think you should...)

Couldn ’ t

 Past inability: I couldn't walk until I was nearly two.

 Impossibility: I couldn't eat another thing!
 Requests: Couldn't you try again?
 Prohibition in the past: My mum used to insist that we couldn't go out until we'd
tidied our bedroom.
 Deduction: It couldn't be Joe, could it? I thought he was away on business.
 Idiomatic: I couldn't agree more! (— I strongly agree)

Could have

 Possibility in the past: Your actions could have had serious consequences.
 Annoyance: You could have told me! (I wish you had told me) I could have
murdered him! (I was very angry with him)

Couldn ’ t have

 Impossibility in the past: He couldn't have taken your car by mistake because he
didn't have the keys.
 Idiomatic: It couldn't have been better. (It was perfect)

May

 Possibility: We may go to France next year.

 Expressing hopes: May you both be very happy.
 Permission: You may go when you've finished.
 Offers: May I be of any assistance?
 Concession: They may live next door but we hardly ever see them.

May not

 Possibility: We may not go to France this year.

 Prohibition: You may not go until you've finished.
 Concession: I may not be very intelligent but I can work out the answer to that
question.

May (not) have

 Possibility in the past: They may not have left yet.

 Concession: He may have written books on the subject, but that doesn't mean
he's a worl expert.

Might

 We use might as the past form of may afte past tense verbs: He said he might
come with us.
 Possibility: This expedition might be quite dangerous.
 Suggestions: You might try phoning directory enquiries.
 Requests: Might I borrow some money?
 Annoyance: You might at least say you're sorry!
 Concession: He might seem rude, but he's not really.

Might not

 We use might not as the past form of may not after past tense verbs: He said he
might not come with us.
 Possibility: You might not like it.
 Concession: He might not wear glasses, but his eyesight is not perfect either.

Might have

 Possibility in the past: They might have been trying to contact us.
 Annoyance: You might have told me! (I wish you'd told me)
 Concession: She might have worked hard, but you wouldn't know it from her
results.

Might not have

 Possibility in the past : They might not have noticed the sign.
 Concession: She might not have done all the work, but she certainly got good
results.

Must

 Deduction: What's that noise? It must be raining.

 Obligation: You must take your shoes off in here.
 Necessity: The wires must touch or it won't work.

Mustn't

 Prohibition: You mustn't worry - you'll be fine.

Must have

 Deduction in the past: I must have left my wallet in the car.

 Necessity in the past: In order to qualify for the job, you must have had several
years' experience.

Mustn't have
 Necessity in the past: You mustn't have had any driving convictions or you
won't get the job.

Shall

 Prediction (I and we): I think we shall get back early next week.
 Intention (7 and we): We shall give our final decision tomorrow.
 Offers (7 and we): Shall I give you a hand?
 Official orders: All the candidates shall remain in their seats until the end of the
examination.
 Asking for advice: What shall we do now?

Shan't

 Prediction: We shan't get back much before ten.

 Intention: I shan't let him do that again.

Shall (not) have

 Prediction: We shall have finished by this evening. (Future Perfect) / We shan't

have another opportunity if we don't win today.

Should/ ought to

(those uses marked * are also appropriate to ought to)

 Giving your opinion*: The traffic should 1 ought to be lighter today.

 Expressing doubt: I should think it will rain today.
 Advice*: You should / ought to go out more often.
 Obligation* (duty): People should / ought to treat each other better.
 Instructions: All visitors should report to reception.
 Conditional: If anyone should phone / Should anyone phone, tell them I'll be
back this afternoon.
 With that-clauses after certain verbs: I suggested that he should take a break.
 With that-clauses after adjectives: It is essential that you should contact us.
 In purpose clauses expressing doubt: They spoke quietly so that nobody should
hear what they were saying.

Shouldn ’ t/ ought not to

(those uses marked * are also appropriate to oughtn't to)

 Advice*: You shouldn't/ oughtn't to drive so fast.
 Obligation* (duty): People shouldn't / oughtn't to be so aggressive.
 Giving your opinion*: The traffic shouldn't / oughtn't to be too bad today.
 With that-clauses after certain verbs: I suggested that he shouldn't work so hard.
 Expressing doubt: I shouldn't think he'd enjoy it.

Should (not) have/ ought to have

 Advice in the past: You should have told me before.

 Giving your opinion* about the past: The traffic should have/ought to have been
lighter earlier today.

Ought (not) to have

 Expressing doubt about the past: I shouldn't have thought he'd have enjoyed it.
 Obligation* (duty) in the past: You should have / ought to have been there hours
ago. They shouldn't have driven so fast.
 With that-clauses after certain verbs: I suggested that he should have taken a
break.

Will

 Prediction: They'll be here soon.

 Predicting the present: They'll be there by now.
 Truths and facts: This car will only run on unleaded petrol.
 Obligation / orders: All passengers will proceed to Gate 7 immediately.
 Habits: She'll always try to help you whenever she can.
 Annoying habits: He will smoke when I'm trying to eat.
 Willingness: I'll give you a hand if you like.
 Intention: I'll put the letter in the post this evening.

Won't

 Prediction: They won't be here for a while.

 Predicting the present: They won't be there yet.
 Truths and facts: This car won't start.
 Refusal: He won't join in unless he's first.
 Intention: I won't come this evening, I'm afraid.

Will (not) have

 Prediction: I won't have finished this book by this evening.

 Predicting the past: They'll have easily got there by now.

Would

 Prediction: They said they would be here soon.

 Predicting the present: I thought they'd be there by now.
 Describing imaginary situations: You'd look better with your hair shorter.
 Habits in the past: She would always try to help you.
 Annoying habits in the past: He would smoke when I was trying to eat.
 Requests: Would you open the door for me?
 Intention in the past: He said he'd put the letter in the post later.
 We use would as the past form of will, e.g. in reported speech.
 Typical (annoying) behavior: It would start raining just as we went out.
 Advice: I'd talk to him about it if I were you.

Wouldn't

 Prediction: They said they wouldn't be here for ages.

 Predicting the present: I thought they wouldn't be here yet.
 Describing imaginary situations: You wouldn't say that if you'd met him.
 Refusal in the past: He wouldn't do what I asked.
 Requests: You wouldn't open the door for me, would you?
 Intention in the past: He said he wouldn't be coming tonight.
 We use wouldn't as the past form of won't, e.g. in reported speech
 Advice: I wouldn't do that if I were you.

Would have/ wouldn't have

 Events in the past which didn't happen: I'd have met you at the station if I'd
known you were coming.
 or which did happen: I wouldn't have told you if I'd known you'd be so upset.
 Tentative thoughts: I'd have thought he'd have jumped at the chance.
 Deductions in the past: I first went to Italy when I was at University; that would
have been in 1982. He promised he would have posted it before five o'clock.
 We use would / wouldn't have as the past form of will / won't have, e.g. in
reported speech after past tense verbs).

Exercise 3. Choose The Right Modal In Each Sentence. Multiple Answers Are Possible.

________ you mind lifting your feet for a moment while I hoover?
 a. Might
b. Can
c. Would
________ you be so kind as to give me some advice?
a. May
b. Could
c. Would
________ I carry that rather heavy-looking case for you?
a. Shall
b. Will
c. Can
________ you possibly come back a little later?
a. Will
b. Could
c. Can
________ you be willing to refund the money we have already paid you?
a. May
b. Would
c. Might
Do you think you ________ stand a little further away?
a. will
b. may
c. could

Exercise 4. Choose The Correct Option To Complete The Following Sentences.

1. All I ________ was a dark blue Lincoln towncar racing round the corner of the street, the girl
reported.
a. can see
b. was to see
c. could see
d. should see
2. The athletes hopes of participating in the Olympic Games later this year ________ because
of a severe knee injury.
a. may have shelved
b. might have to be shelved
 c. must have been shelved
d. were allowed to be shelved
3. They ________ about safety problems before they launched their project.
a. should have known
b. must know
c. could know
d. need to know
4. The Green Line ________ as a good film since most of the characters are well drawn and it is
beautifully filmed.
a. may have to be rated
b. might be rated
c. can’t have been rated
d. needs to rate
5. There ________ a competition between the spate of online universities and the old
traditional long established schools in the months to come.
a. may have
b. may have been
c. might be
d. could have
Exercise 5. Choose The Correct Option To Complete The Following Sentences.

1. Scientists have found that people who are active at a moderate level
experience a long list of health benefits and that physical activity ________
vigorous.
a. has to be
b. must be
c. needn't be
2. You ________ the locksmith to open the door for you last night before
you tried to open the door yourself.
a. must call
b. ought to have called
c. had better call
3. When an emergency vehicle is approaching with its lights and siren on,
drivers ________ pull over and stop to get out of the way.
a. must move
b. needn’t have moved
c. must have moved
4. The prisoner ________ this way; there are no footprints at all.
 a. can’t have escaped
b. could have escaped
c. may have escaped
5. My girlfriend said I ________ her anything for her birthday, but I think I
________ her some flowers at least or a nice bottle of wine.
a. didn't need to buy / should buy
b. should have bought / must buy
c. may not buy / may have bought