1. MODAL VERBS

2. MODAL VERBS Only used in one form
( no past, no –ing form, no –s in 3rd person singular)
Negative : place not after the modal verb
never conjugated
MODAL VERBS
Always come before subject in interrogative sentences
Express an idea (possibility,necessity,
obligation etc
Always followed by a main verb in the base form

3. CAN PERMISSION OR REQUEST Can I call you later? ABILITY/INABILITY
I can play the piano.
OPPORTUNITY TO DO SOMETHING/POSSIBILITY
I´m free tonight so we can go out.

4. CAN – affirmative and negative forms
You He
She It We
they
+ CAN
CAN´T CANNOT
Verb in the base form
+ complements
ATTENTION!
Can´t/cannot indicate impossibility

5. MAIN VERB IN THE BASE FORM
CAN – negative form I
You He
She It We
they
MAIN VERB IN THE BASE FORM +
COMPLEMENTS ?
CAN

6. COULD PAST ABILITY PAST OF CAN POSSIBILITY
When I was young, I could ride a bike.
PAST OF CAN .
POSSIBILITY
I think we could have another Gulf war.
MORE POLITE THAN CAN (REQUEST)
Could you open the door, please?

7. COULD – affirmative and negative forms
YOU HE
SHE IT WE
THEY
+ COULD
COULD NOT
COULDN´T
MAIN VERB IN THE BASE FORM +
COMPLEMENTS
ATTENTION!
COULD NOT
Suggests that it´s impossible for something to happen

8. COULD – interrogative form
YOU HE
SHE IT WE
THEY
MAIN VERB IN THE BASE FORM +
COMPLEMENTS ?
COULD

9. DEDUCTION OR CENTAINTY
MUST
OBLIGATION
(“must” involves the speaker´s authority or opinion)
You must go to bed, said her mum
DEDUCTION OR CENTAINTY
That must be Jerry, they said he is tall and has red hair.

10. MUST – affirmative and negative
+ MUST
- MUST NOT
MUSTN´T
MAIN VERB IN THE BASE FORM +
COMPLEMENTS

11. You must not swim in that river, it is full of crocodiles
MUST NOT = MUSTN´T
PROHIBITION
You must not swim in that river, it is full of crocodiles

12. MAIN VERB IN THE BASE FORM
MUST - interrogative 
MAIN VERB IN THE BASE FORM +
COMPLEMENTS ?
MUST

13. Polite permission or request
MAY
Possibility
He may run the marathon this year
Polite permission or request
May I go now? Yes, you may

14. MAY – affirmative and negative forms
MAIN VERB IN THE BASE FORM +
COMPLEMENTS
+ MAY
- MAY NOT
ATTENTION!
THERE IS NO ABBREVIATION FOR MAY NOT

15. MAIN VERB IN THE BASE FORM
MAY - interrogative 
MAIN VERB IN THE BASE FORM +
COMPLEMENTS ?
MAY

16. To say that you are not sure that something is going to happen
MIGHT
To say that you are not sure that something is going to happen
She might come to my house later.

17. MIGHT – affirmative and negative forms
- MIGHT NOT
MAIN VERB IN THE BASE FORM +
COMPLEMENTS 
ATTENTION!
IT´S NOT USUALLY USED IN INTERROGATIVE FORM.

18. MAY x MIGHT x COULD

19. I have to wear a uniform in my school
HAVE/HAS TO
OBLIGATION
( based in a law or rule)
I have to wear a uniform in my school

20. She doesn´t have to finish her composition tonight
DON´T/DOESN´T HAVE TO
It is not necessary to do something, you can do it if you want but it is not necessary
She doesn´t have to finish her composition tonight

21. HAVE/HAS TO – affirmative form
She He it
MAIN VERB IN THE BASE FORM +
COMPLEMENTS
HAS TO I
YOU WE
THEY
MAIN VERB IN THE BASE FORM +
COMPLEMENTS
HAVE TO

22. HAVE TO – interrogative form
MAIN VERB IN THE BASE FORM +
COMPLEMENTS ? He
She It
HAVE TO
DOES
MAIN VERB IN THE BASE FORM +
COMPLEMENTS ? I
YOU WE
THEY
HAVE TO DO

23. SHOULD ADVICE SUGGESTIONS CRITICISM EXPECTATIONS
This film should be good.
You should stop smoking.
You shouldn’t have done it!

24. SHOULD – affirmative and negative forms
+ SHOULD
SHOULD NOT
SHOULDN´T
MAIN VERB IN THE BASE FORM +
COMPLEMENTS

25. SHOULD – interrogative form
MAIN VERB IN THE BASE FORM +
COMPLEMENTS ?
SHOULD

26. HAD BETTER
GIVE ADVICE
It is stronger than should and means that if the person doesn’t follow the advice, s/he can have negative consequences.
You had better not eat so much. The doctor told you that you are overweight.

27. HAD BETTER – affirmative and negative forms +
HAD BETTER
´D BETTER -
HAD BETTER NOT
´D BETTER NOT
MAIN VERB
IN THE BASE FORM +
COMPLEMENTS
ATTENTION!
IT´S NOT OFTEN USED IN THE INTERROGATIVE

28. OUGHT TO Advice or recommendations Assumption or expectation
Strong probability(often with the idea that something is deserved)
You ought to stop smoking.
Jim ought to get the promotion.
This stock ought to increase in value.
Mark ought not drink so much

29. OUGHT TO – affirmative and negative forms +
Ought to -
Ought not
Main verb in the base form +
complements
ATTENTION!
NOT USED IN INTERROGATIVE

30. Shall we go to the movies?
SUGGESTION
Shall we go to the movies?
ONLY USED IN INTERROGATIVE AND AFFIRMATIVE 1ST PERSON SINGULAR AND PLURAL