1. MODAL VERBS
BACHILLERATO

2. Characteristics
They are INCOMPLETE VERBS. They don’t have all the tenses. There is not past participle, so there is not passive. They use other verbs to complete the tenses.
- CAN is completed with BE ABLE TO
“They can play the piano.”
“They will be able to play the piano in the future.”
- MUST is completed with HAVE TO
“You must come early.”
“You had to come early yesterday.”

3. They don’t have –s in third person singular of the present simple
“ He can open the door”
“ She must come early”

4. They are followed by an infinitive without 'to' in most cases.
BUT:
NEED takes 'to' when expressing absence of obligation in the negative:
You do not need to stay if you don't want to.
OUGHT TO is a special case and you must learn it like that. It expresses convenience.
Ex: You ought to study more more if you want to pass the exam.

5. They don’t need auxiliary verb in the interrogative or negative form
“ Can I help you?”
“ We shouldn’t go to the toilet”

6. PROBABILITY/
POSSIBILITY
ABILITY
PERMISSION
OBLIGATION/
ADVICE
OFFERS
CAN
I can play the piano
Can I go out tonight?
CAN’T
She can’t be his mum. She ‘s too young
I can’t speak German
Can I borrow the car? No, I can’t.
MIGHT
It might rain tomorrow
MAY NOT
MIGHT NOT
If the bus doesn’t arrive soon, we may not see the start of the film
COULD
It could rin tomorrow
I could already read when I was two
Could I see your passport please, sir?
MAY
It may rain tomoroww
May I leave the table?
MUST
She must be his sister because they look alike.
You must leave before the clock strikes twelve.
HAVE TO
I have to study tonight.
SHOULD /
OUGHT TO
You should see it. It’s excellent.
HAD BETTER
You had better sleep more.
WOULD
Would you like a drink?

7. MODALES PERFECTOS
Son modales que se refieren siempre a acciones ocurridas en el pasado.
FORMACIÓN:
MODAL + HAVE + PARTICIPIO PASADO
Ejemplos:
It must have been a difficult decision
They should have invited her to their wedding

8. MODAL PERFECT USES EXAMPLES MUST HAVE + P.P.
Conclusión lógica sobre un hecho del pasado
Linda has arrived late. She must have been in a traffic jam
MAY / MIGHT HAVE + P.P.
Una suposición sobre algo pasado
She may / might have taken the wrong bus.
COULD HAVE + P.P.
Habilidad de haber hecho algo pero finalmente no lo hizo
You could have asked the doctor before taking that medicine
COULDN’T HAVE + P.P.
Certeza de que algo no pudo haber sucedido
He couldn’t have gone to the concert because he was doing a test
WOULD HAVE + P.P.
Quiso haber hecho algo, pero no pudo hacerlo por causas externas
I would have gone to the party, but I was too busy
SHOULD / OUHT TO HAVE + P.P.
Queja de que algo haya ocurrido en el pasado o lamento de que no se haya cumplido lo que esperábamos
You should / ought to have warned me earlier
SHOULDN’T HAVE + P.P.
Crítica sobre un acontecimiento pasado que no debería haber ocurrido
He shouldn’t have forgotten about her birthday
NEEDN’T HAVE + P.P.
No había necesidad de hacer lo que se hizo en el pasado
You needn’t have brought anything to my party.