MODAL VERBS

What are modal verbs?

• Modal verbs (also called modal verbs, modal auxiliary verbs, modal auxiliaries) are special verbs that give additional information about the function of the main verb.

• Examples : CAN, COULD, SHALL, SHOULD and so on.

• Types of modal verbs 1.Advice 2.Obligation 3.Permission

Modals• Modals in the present: You should see a doctor.

• Modals in the past: You should have seen a doctor

MODAL VERB + INFINITIVE (V.1) + PAST PATICIPATE (V.3)

MODAL VERB + INFINITIVE (V.1)

Advice

Modal Verbs OF

- Use to give advice and make recommendations.- For example: - I think you shouldn’t lazy to do your homework.- We should wake up in early morning because we must go to

school.• Should is used for advice in the present.

Subject + Should + Base Verb• Should is used for advice in the past.

Should + Have + Past Participle• For negative advice.

Shouldn't

Should

Ought to

- Similar to should but less common speech and usually not used in negative way

- For example: - You ought not to steal your mother’s money.- You ought to study hard for the bright future.• For negative advice

Ought not to

Had better

- Stronger and more urgent than should or ought to, so it used to give stronger advice and warning

- For example:- It looks like rain, you had better take an umbrella. - She had better hurry up because the train leaves

in 5 minutes.• For negative advice

Had better not

Obligation

Modal Verbs OF

Obligation

• OBLIGATION means something by which a person is obliged to do, and which arises out of a sense of duty or results from custom, law, and so on.

• We can use• - have to + infinitive (V.1)• - must + infinitive (V.1)• - should + infinitive (V.1)• to express obligation (Something you have to do)

Have to / Don't have to

Positive Obligation Negative Obligation☀ Use for strong obligation☀ This is usually referring to a rule or law

Examples:-Children have to go to school.-You have to be careful with scissors.

☀ Use "Don't have to" to show something that is not necessary

Examples:-I don't have to work on Sundays.-You don't have to eat anything you don't like.

Had to /Didn't have to

Positive Obligation Negative Obligation☀ Obligation in the past

Example:-I had to wear a school uniform when I was a child.

☀ No obligation in the past

Example:-We didn't have to go to school on Saturdays.

Must (Must Have) / Mustn't

Positive Obligation Negative Obligation☀ Strong obligation (possibly based on the speaker's opinion): I must study today.☀ It is formal and normally used in writing:You must use a pencil on the test.☀ Logic/Certainty or strong probability.: She must be hungry because she has not eaten for 2 days.☀ MUST HAVE: use in supposition: I can't find my laptop, I must have left it in the train.

☀ "Must not" shows something that is prohibited

Examples:-You mustn't smoke here.-You mustn’t eat in the computer room. (Food in the computer room is prohibited.)

SPECIAL EXAMPLE

• Take care to distinguish correctly between "had to" and "must have"

• They had to go to Thailand.= They were obliged to go to Thailand.Vs.• They must have gone to Thailand. = In my opinion, they have certainly gone to Thailand.

Should have + past participle /Shouldn't have + past participle

Positive Obligation Negative Obligation☀ A past action which didn't happen.

Example:-You should have gone to bed earlier, now you have missed the train.

☀ A past action which didn't happen.

Example:-You shouldn't have taken that job, it was a bad idea.

SPECIAL EXAMPLE• Here is an example of the difference between 'have to' and

'must':

• -My doctor said that I have to stop smoking or I'll risk serious problems. (I have no choice)

Vs.• -I must stop smoking. It’s costing me too much money. (It’s

my decision)

NOTE TO SELF:

• Be careful about the difference between don't have to and mustn't!

• Don't have to means you don't need to do something, but it's fine if you want to do it:

• -I don't have to get up early at the weekend (of course, if I want to get up early, that's fine, but I can stay in bed if I want).

• Mustn't means it's not allowed, or it's a bad idea:• -You mustn't eat so much chocolate, you'll be sick.

Should (Ought to) /Shouldn't

Positive Obligation Negative ObligationMild obligationAdviceLogic/Conclusion

Examples:-You should save some money.-I ought to get a haircut

Mild negative obligationAdvice

Examples:-You shouldn't smoke so much.

Should and ought to are more or less synonymous

Example:-You should stop smoking. = You ought to stop smoking.

Permission

Modal Verbs OF

Definition of PERMISSION

: the right or ability to do something that is given by someone who has the power to decide if it will be allowed or permitted

 Ask For Permission

• We often use “can” to ask for permission.Ex. Can I go home now? Can we eat this pizza?

• Could is more formal and polite than can. Ex. Could I play a video games?

Could I smoke at the school?

• May is another more formal and polite way.Ex. May I go to shopping?May I drink water?

Give Permission• We also often use “can” to give permission

Ex. You can go home now.

You can eat this pizza.

• Could is more formal and polite than can, and we use could to say that something was permitted in the past

Ex. You could play a video games .

You could smoke at the school 15 years ago.

• May is more formal and polite way to give permission

Ex. You may go shopping.

You may drink water.

Refusing Permission• We use “can’t” to say that something isn’t permitted.

Ex. You can’t go how now.You can’t eat this pizza.

• We use “couldn’t” to say that something was not permitted in the past.Ex. You couldn’t smoke in the bus.You couldn’t do exercise in the toilet.

• We can also use “may” to say that something isn’t permitted too.Ex. No, you may not.

TEST YOURSELF

• You don’t look very well, you __________ go to work.

had better not

TEST YOURSELF

• Mrs. Johnnie's body was found in the lounge just moments ago, and it's still warm! Nobody has left the mansion this evening, so the killer ______ be someone in this room. It ______ be any one of us!!!

must coul

d

TEST YOURSELF

• She __________ get up early today, because it's Sunday.

doesn’t have to

TEST YOURSELF

• You ______ tell anyone what I just told you. It's a secret.

mustn’t

TEST YOURSELF

• Ned: ______ I borrow your lighter for a minute?

Sarah: Sure, no problem. Actually, you ______ keep it if you want to. I've given up smoking.

Can

can

Thank you for listening.

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