AbilityLogical conclusionNecessityObligationPermissionPossibilityProhibitionRequestsAdvice

Can, could• I can remember all my friends’ telephone numbers.•He could swim by the time he was 3.

Can’t be, must be•Ann isn’t answering the phone. She must be out.•This can’t be the South Pole.There aren’t any penguins.

Must/can’t have V3•You must have been tired after all that hard work last week.•You can’t have been tired last Sunday – you slept for hours.

have to, don’t have to•I have to cycle to school. It’s too far to walk.•I don’t have to go to school today – it’s a national holiday.

Must, mustn’t•You must do this homework carefully.•You mustn’t steal other people’s things. It’s wrong.

Had to•We had to stay behind after the lesson and do someextra work.

Can, could, may•You can borrow my bike, but you can’t have the car.•Could my friends come to stay next weekend?•May I speak loud here?

May, might•Ann is not in class. She might be in the library.•Sam may come to the cinema with us – I’m not sure if he’s free.

Mustn’t•Students mustn’t use a dictionary in the exam.

Can,could, would•Can you tell me the time, please?•Could you pass me the salt?•Would you mind pouring me some water?

should•You should write to your family.

Should have V3

•You should have written to your family.(but you didn't.)

Could have V3

•You could have tried a new method (but you didn't choose to.)

Ability

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should

can

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might

Abilitycancould

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may might

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must be

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Permissioncan

couldmay

Prohibitionmustn’t