Modal Auxiliaries

Prof. Rinkerman

Modal Auxiliaries

• Modals don’t have an –s, -ed, or ing ending.– He can drive (NOT: He cans

drive)

• Don’t use an infinitive with modals– He can go. (NOT: He can to go)

• To form the negative, put NOT after the modal– He should not go.

Some Examples• We can play football.• We could play football.• We may play football.• We might play football.• We must play football.• We mustn't play football.• We ought to play football.• We shall play football.• We should play football.• We will play football.• We would play football.

NegativesPositive negativelong form short formlong form short

formCan -- cannot can'tCould -- could not couldn'tMay -- may not --Might -- might not mightn'tought to -- ought not to oughtn't toshould ‘d should not shouldn'tWill 'll will not won'tWould 'd would not wouldn't

CAN Use Examplesability to do something In the present (to be able to) I can speak English.

permission to do something In the present (to be allowed to) Can I go to the cinema?

Request Can you wait a moment, please?

offer I can lend you my car till tomorrow.

Suggestion Can we visit Grandma at the weekend?

Possibility It can get very hot in Arizona.

COULD Use Examples• ability to do something In the PAST (to be able to) I could walk when I was two.

• Permission to do something In the Past (to be allowed to) I could go to the movies when I

I was a teenager. • polite question Could I go to the cinema, please?• polite request Could you wait a moment, please?• polite offer I could lend you my car till tomorrow.

• polite suggestion Could we visit Grandma at the weekend?• possibility It could get very hot in Montana.

MAYUse Examples• Possibility It may rain today.

• Permission to do sth. in the present (substitute form: to be allowed to) May I go to the

cinema?

• polite suggestion May I help you?

MIGHTPossibility It might rain tomorrow

(*less possible than MAY)

Polite question: (not very common)Might I borrow your pen?

SHOULD Advice (it’s good – it’s a good idea /

not good to do or bad idea)

You should exercise.

You shouldn’t smoke.

Ought to = should

Advice

You ought to drive carefully.

I ought to study tonight.

MUST (HAVE TO)Necessity: must = need to, have toI must go to the supermarket today.I have to go to the supermarket today.

Legal terms – You have no choice

You must have a valid driver’s license.You have to have a valid driver’s license.

Strong Possibility (95% sure)

You’ve been driving for 10 hours. You must be tired. (You have to be tired)

Must + Not / Mustn’t

Prohibition

You mustn’t drive without a valid license.

You mustn’t drink and drive.

Must / Have to

Must = have toWe must talk about it.We have to talk about it.

Mustn’t = don’t have to(strong obligation (don’t have the need)not to do something)

We mustn’t talk about it. (We have a strong obligation NOT to talk about it)

We don’t have to talk about it. (There is no need)

MUSTN’T versus DON’T HAVE TO• We use 'mustn't' to express strong obligations

NOT to do something. (You have NO CHOICE)

We mustn't talk about it. It's confidential. I mustn't eat chocolate. It's bad for me. You mustn't phone me at work. We aren't

allowed personal calls. They mustn't see us talking or they'll suspect

something.

• We use 'don't have to' to state that there is NO obligation or necessity. (You can if you want, but you don’t have to)

We don't have to get there on time. The boss is away today.

I don't have to listen to this. I'm leaving. You don't have to come if you don't want to. He doesn't have to sign anything if he doesn't

want to at this stage. I don’t have to go. Only if I want to.

Will

• Request / Demand / Order (less polite than would)

Will you please close the door?

• Prediction / AssumptionI think it will rain on Saturday.

• PromiseI will stop smoking.

• Spontaneous DecisionCan someone give me a ride? I will.

Would

• Wish / Request (more polite than will)

Would you close the door, please?

ExerciseDecide if the sentences have the same

(similar) or different meaning.

Example:1a. Would you like to go to a movie? 1b. Do you want to go to a movie?

S (same) or D (different)?

2a. We will not go to New York.2b. We should not go to New York.

S (same) or D (different)?

Same or Different?1a. You should go to the doctor.1b. You can go to the doctor.

2a. I may buy a new car. 2b. I must buy a new car.

3a. Could you help me later?3b. Would you help me later?

4a. She must not driver her car.4b. She doesn’t have to driver

her car.

Same or Different?

5a. She has to leave immediately.5b. She must leave immediately.

6a. We will have a test soon. 6b. We may have a test soon.

7a. I can’t go to the party.7b. I might not go to the party.

8a. You shouldn’t buy a car.8b. You mustn’t buy a car.

Same or Different?

9a. May I use your phone?9b. Could I use your phone?

10a. He might not eat lunch.10b. He may not eat lunch.

11a. I should go to the doctor.11b. I must go to the doctor.

12a. I have to take my passport with me.

12b. I may take my passport with me.