1. MODAL VERBS
2nd of Bachillerato

2. DEFINITION MODALS ARE SPECIAL VERBS WITH THE FOLLOWING FEATURES:
1. THEY DO NOT CHANGE IN TERMS OF PERSON, GENDER OR NUMBER
He can speak four languages / You can write Chinese
2. THEY FORM THE NEGATIVE AND THE INTERROGATIVE FORMS WITHOUT DO
Must she do her homework? / We shouldn’t smoke
3. THEY ARE FOLLOWED BY THE BASE FORM OF A VERB (INFINITIVE OR PERFECT INFINITIVE)
They may come to see us / I must have talked to her before leaving
4. THEY DO NOT HAVE INFINITIVE, GERUND, PARTICIPLE, FUTURE FORMS OR COMPOUND TENSES
*to can, *canning, *canned, *will can, *have been canning/*is canned/etc.
5. THEY ARE USED LIKE ‘AUXILIARY VERBS’ IN SHORT ANSWERS, QUESTIONS TAGS & WITH SO, NEITHER, NOR
‘Must I wear a uniform?’ ‘Yes, you must’
You can’t lend me a pound, can you?
They ought to study harder for the exams. So ought we.

3. SEMI-MODALS & NEED TO
BE ABLE TO & HAVE TO ARE SEMI-MODAL VERBS BECAUSE THEY
SHARE MOST OF THE CHARACTERISTICS OF MODAL VERBS EXCEPT
THAT THEY CAN BE CONJUGATED
I would like to be able to stay here.
You’ll be able to walk soon.
Have you been able to solve the problem?
When I was young I had to get up at 5 o’clock in the morning.
They had had to train hard before the athletics competition took place.
NEED TO IS NOT A MODAL, NOR A SEMI-MODAL, BUT IT SHARES SOME
OF THEIR USES AND MEANINGS
One needs to have a visa to go to the U.S.A.
He needs to get a new pair of trousers.

4. CAN / BE ABLE TO / CAN’T CAN expresses:
a) General ability or capacity to do sth  She can lift me up with one hand
b) Possibility  Even expert drivers can make mistakes
c) Ask for and give permission  Can we borrow these books?
d) Offers, suggestions & requests  I can help you with the washing up.
We can talk about that later.
Can you come here a minute, please?
BE ABLE TO expresses:
a) General ability to do sth 
One day people will be able to run a kilometre in two minutes
We have been able to cook the dinner on time.
b) Particular ability to do sth on a specific situation in past (with the meaning of manage to, succeed in)
How many eggs were you able to eat at the festival competition?
How many eggs did you manage to eat at the festival competiton?

5. CAN / BE ABLE TO / CAN’T CAN’T expresses:
a) Lack of ability or capacity  I can’t cook a Spanish omelette.
b) Impossibility  Humans can’t fly on their own.
c) Prohibition  You can’t speak loudly at the hospital.
d) Negative deduction or certitude that sth is impossible 
They can’t be at home. The lights are off.
That can’t be the postman, it’s only seven o’clock.

6. COULD COULD is the past form of CAN and it expresses:
a) General ability or capacity to do sth in the past 
He was a terrific liar: he could make anybody believe him.
b) Polite requests  Could I see you tomorrow evening?
c) Less direct suggestions or offers 
I could do the shopping for you, if you’re tired.
d) More remote possibility 
Her performance was the best that could be hoped for.

7. MAY / MIGHT MAY expresses:
a) Possibility  We may go climbing in the Alps next summer.
b) Ask for or give permission  May I put the TV on?
Visitors may not feed the animals.
c) Ask for sth  May I have some more wine, please?
MIGHT expresses:
a) Less possibility 
Peter might phone. If he does, could you ask him to ring later?
b) Ask for permission (more formal)  Might I sit on this chair?

8. WOULD / SHALL SHOULD / OUGHT TO
WOULD expresses:
a) Polite requests  Would you open the window, please?
b) Together with like, offers & invitations  Would you like a cup of tea?
SHALL expresses:
a) Offers  Shall I carry your bag?
b) Suggestions  Shall we go to the concert?
c) Requests for insructions  How shall I cook the chicken?
d) Requests for avice  What shall I do?
SHOULD / OUGHT TO express:
a) Advice or opinion  You should go and see Mary.
*Slight difference of use: should is used to give a subjective opinion or personal advice; ought to has a more objective force (talking about laws, duties & regulations).
People ought to vote even if they don’t agree with any of the candidates

9. MUST / HAVE TO MUST expresses:
a) Obligation (more commonly used when the obligation comes from the
speaker, in present)  I really must stop smoking.
You must be here by 8 o’clock at the latest.
b) Logic deduction about a present event (to say that we are sure about sth
because it’s logical)  Mary must have some problem: she keeps crying.
There’s the doorbell. It must be Roger.
HAVE TO expresses:
a) Obligation (more commonly used when the obligation comes from ‘outside’
–a rule, an order, etc., in present; anytime in other tenses) 
I have to work from 9 a.m. till 5 p.m.
Did you have to go to church on Sundays when you were a child?

10. NEED TO / NEEDN’T
NEED TO is not a modal, nor a semi-modal, but it is used in affirmative
sentences to express:
a) Obligation  One needs to have a visa to go to the U.S.A.
b) Necessity  He needs to get a new pair of trousers.
NEEDN’T is a modal and it expresses:
a) Lack of necessity or obligaton  You needn’t try to explain.
We needn’t book a table, the restaurant won’t be full tonight.

11. DON’T HAVE TO / MUSTN’T DON’T HAVE TO expresses:
a) Lack of necessity or obligaton  You don’t have to come early tomorrow.
MUSTN’T expresses:
a) Prohibition  You mustn’t move any of the papers on my desk.

12. PERFECT MODALS
MUST HAVE + participle expresses a logical deduction about a past event
(certainty that sth was true) 
The lights have gone out. A fuse must have blown.
MAY / MIGHT HAVE + participle expresses a guess about a past action 
Polly’s very late. She may have missed the train.
‘What do you think that noise was?’ ‘It might have been a cat.’
COULD HAVE + participle expresses ability to do sth in the past which in the
end was not done  I could have married anybody I wanted to (but I didn’t).
COULDN’T HAVE + participle expresses certainty that sth did not happen 
I couldn’t have won, so I didn’t go in for the race.

13. WOULD HAVE + participle expresses desire to do sth in the past which in
fact couldn’t be done  She would have arried earlier but she was delayed.
SHOULD / OUGHT TO HAVE + participle expresses a criticism or regret
after an event  I wonder where she is. She should have arrived by now.
I ought to have gone out last night. I’m sorry I didn’t.
SHOULDN’T HAVE + participle expresses a criticism or regret after an event
You shouldn’t have told him anything about our conversation.
NEEDN’T HAVE + participle expresses an unnecesary past action 
I needn’t have bought all that wine, only three people came to the dinner.