MODAL VERBS

MODAL AUXILIARIES

Modal auxiliaries are special verbs. They add extra meaning to the main verb. Most modals have more than one use.

FORMATION

- Use modal auxiliaries with the stem of the main verb. Don't add -s in the 3rd person singular.

She can speak Chinese and Russian.

- Make interrogative sentences by changing the word order.

Could you call me back?

- Make negative sentences by adding not to the modal verb.

I cannot imagine what this is goint to be like.

You shouldn't lose your temper with people.

BE CAREFUL

- Don't use do as auxiliary verb to make negative and interrogative sentences with modal verbs.

Never*Do you can swim?: Can you swim?

- Don't use to after modal verbs (with the exception of ought to).

Never*We must to study hard: We must study hard

- Don't use two modal verbs together.

Never*We would must visit her: We should visit her

MODAL AUXILIARIES EXAMPLES

ABILITY AND PERMISSION: 
can, could, may, 
 be able to, be allowed to

CAN

*Ability (present): I can play the piano.

*Permission(informal): Can I go to the toilet, please?

You can use the telephone if necessary.

COULD

*Ability in the past : I could swim at the age of 3= I was able to swim...

*Permission in the past: When he was a little boy, he could/was allowed to play outdoors

MAY

*Permission (very formal) : May I borrow your car?

BE ABLE TO (not a modal verb, used instead of “can “ for different verbal tenses)

*Ability(=can): He will be able to visit you next week.

We were able to find the house althoug we had no map.

BE ALLOWED TO (not a modal verb, used instead of “can “ for different verbal tenses)

*Permission: I won't be allowed to go the party.
PROBABILITY and CERTAINTY:
may, might, could, must, can't

MAY

*Probability: She may be at home.

The keys may be in the car

MIGHT ( weak probability,less likely than may)

* Probability: She might be at home.

They keys might be in the car

COULD ( weak probability,less likely than may)

*:Probability She could be at home

The keys could be in the car.

MUST

*Certainty, deduction: She must be at home: the lights are on.

The keys must be in the car. I've been nowhere else

CAN' T
*Negative certainty, deduction, impossibility, He can't be the same person, he looks completely different!

She can't be at home, it's Saturday and she always goes out on Saturdays.

The keys can't be in the car. I've already looked there.

ADVICE: should, ought to, had better.

SHOULD

*Advice: You should visit the dentist every year.

OUGHT TO

*Advice: You ought to visit the dentist every year.

HAD BETTER

*Advice: We'd better hurry or we'll be late.

OBLIGATION, PROHIBITION, ABSENCE OF OBLIGATION AND NECESSITY  : must, have to, needn't

MUST

*(Personal) Obligation: I must study hard to pass my test.

HAVE TO  (not a modal verb, it can be conjugated as an ordinary verb))

*(External )Obligation: You have (got) to take your shoes off before you get into the mosque
  She has (got) to help at home.

MUSTN'T 

*Prohibition: You musn't smoke in hospitals. 

DON'T HAVE TO =NEEDN'T

*Absence of obligation: I don't have to pay until September.
She doesn't have to pay, I will pay.
You needn't come today if you don't want to

The modal need  can be used in negatives and questions to express absence of obligation.
Need I not go?

NEED TO (not a modal verb, it can be conjugated as an ordinary verb))
*Necessity: I need to go
                    They needed to earn some money

OFFERS AND REQUESTS: will, would, shall, can, could

WILL

*Polite request: Will you pass me the sugar, please?

*Offers: Will you have some tea?

WOULD

*Polite request: Would you speak more slowly, please?

*Offers: What would you like to drink?

*Preference: I would rather have tea.

*Repeated past action: I would walk on the beach every morning when I was living in Brighton

SHALL

*Offer: Shall I call a taxi for you?

*Suggestion: Shall we ask for volunteers?

CAN, COULD

*Request: Can you lend me 10 euros, please?

*Polite request: Could you lend me 10 euros, please?