Modal Auxiliaries

Auxiliary + the simple form of the verb

Can= I can speak English

Could= He couldn’t come to class

May= It may rain tomorrow

Might= It might rain tomorrow

Should= Mary should study harder

Had better= I had better study tonight

Must= Joe must see a doctor today

Will=I will be in class tomorrow

Would= Would you please close the door?

EXPRESSING ABILITY: CAN AND COULD

Can expresses ability in the present or

future

- Bob can play the piano

- You can buy a screwdriver at a hardware

store

The negative form of can may be written :

Can’t, cannot or can not

The past form of can is could

- Our son could talk when he was two

years old

The negative of could: couldn’t or could

EXPRESSING POSSIBILITY: MAY AND MIGHT

EXPRESSING PERMISSION: MAY AND CAN

May and Might express possibility in the present or future. They have the same meaning.

- It may rain tomorrow

- It might rain tomorrow

The negative: may not or might not

Maybe (spelled as one word) is an adverb meaning perhaps

- Maybe it will rain tomorrow

- Maybe John is sick

- John may be sick (spelled as two words) is a verb form may + main verb be

ASKING FOR PERMISSION: MAY I, COULD I, CAN I

People use may I, could I, and can I to ask polite questions. The questions ask for someone’s permission.

- may I please borrow your pen?

- Could I ask you something?

- Can I come to your house tonight?

Possible answers: Yes, Yes of course, Yes certainly, Of course, certainly.

Informal: Sure, Okay, Uh huh

ASKING FOR ASSISTANCE: WOULD YOU,

COULD YOU, WILL YOU, CAN YOU

People use would you, could you, will

you, and can you to ask polite

question. The questions ask for

someone’s help or cooperation.

- Would you please open the door?

- Could you help me please?

- Will you turn the music down? It’s

too loud

- Can you buy something for dinner?

POSSIBLE ANSWERS:

Yes, of course

Yes. Certainly

Of Course

Certainly

I’d be happy to

I’d be glad to

Of course I’d be happy to

EXPRESSING ADVICE: SHOULD, OUGHT

TO, HAD BETTER

Should, ought to, and had better have basically the same meaning. They mean “this is a good idea, or this is a good advice”. My clothes are dirty I (should/ought to/had

better) wash them

The negative of should is should not (shouldn’t)

Had better (contraction of had= ‘d)

-You’d better study tonight.

EXPRESSING NECESSITY: HAVE TO, HAVE GOT TO, MUST

Have to, have got to, and must have basically the same meaning. They express the idea that something is necessary.

- I have to/have got to/must study tonight

Have to is used much more frequently than must in everyday speech and writing.

The past form of have to/have got to/must is had to (meaning necessity).

Expressing Lack of Necessity: do not have to

Expressing Prohibition: Must not

Don’t/doesn’t have to expresses the idea that something is not necessary.

- I finished all of my homework this afternoon. I don’t have to study tonight.

- Tomorrow is a holiday, Mary doesn’t have to go to the class.

Must not expresses prohibition (DO NOT DO THIS!)