1. Modals
Permission
Obligation / Prohibition
Probability / Possibility
Suggestion / Advice

2. Permission Can / May
Situations:
Ask
Give Ask:
Refuse 1. Can I come in? (informal)
2. May I come in? (formal)
Give:
1. Of course, you can call me later, no problem.
Refuse:
1. I'm sorry, you can't. I'm too busy right now.

3. Ability Can = be able to
Ask:
1. Can you speak English? Or
2. Are you able to speak English?
3. Can you swim?
Replies
1. Of course, I can.
2. Of course, I m able to.
3. Definitely. I am a very good swimmer.
4. No, I can t.
5. No, I m not able to speak Englisn.
6. Not really. I m a lousy swimmer.

4. Possibility / Probability
Can / Could
May / Might
Should
1. It may rain today. / It might rain today.
2. Look at the sky. It s turning darker. It can rain today.
3. Thank God, it could have been you.
4. They should visit the Zoo in SPaulo. It s wonderful.
5. You should not talk this way. People can not understand you.

5. Obligation
Must / Have to
1. You have to/must study hard.
2. Does he have to pay for this ticket?
Must he pay for this ticket?
3. They don t have to go immediately.
4. I must/have to be in time for the class.
5. We must/have to be consistent to our way of thinking.

6. Prohibition Must not = Mustn't
1. You mustn't go out dressed like this. Change yourself or you'll
stay home.
2. They mustn't step on the grass.
3. The students mustn't come to school without their uniforms.

7. Suggestion Should
1. You look pale. You should see a doctor.
2. What do you think I should do?
3. Should the teacher be more rigid?

8. CAN
Ben ___________ play
soccer.
CAN
COULD
MUST
HAVE TO
MAY
MIGHT
SHOULD

9. Mr. and Mrs. Davies
COULD
___________ play volleyball 10
years ago.
CAN
COULD
MUST
HAVE TO
MAY
MIGHT
SHOULD

10. Mr. White cannot run this
marathon because he doesn t feel
good. What do you think?
SHOULD
I think he ____________ take
some pills to feel better.
CAN
COULD
MUST
HAVE TO
MAY
MIGHT
SHOULD

11. Mr. and Mrs. Davies look tired.
They ____________ rest now.
MUST
CAN
COULD
MUST
HAVE TO
MAY
MIGHT
SHOULD

12. Mandy has bad grades. She
________ study more.
MUST
CAN
COULD
MUST
HAVE TO
MAY
MIGHT
SHOULD

13. Rick has a test tomorrow. His
mother says: “Son, you
MUST
__________ go to your room to
study.”
CAN
COULD
MUST
HAVE TO
MAY
MIGHT
SHOULD

14. Mr. Benson is a musician. He
________ play the violin.
CAN
CAN
COULD
MUST
HAVE TO
MAY
MIGHT
SHOULD

15. Mr. Benson was a musician in the
past. He ________ play the violin.
COULD
CAN
COULD
MUST
HAVE TO
MAY
MIGHT
SHOULD

16. Jane and Mary waits for the bus
for a long time. What do you
suggest them to do?
In my opinion, they __________
SHOULD
listen to some music.
CAN
COULD
MUST
HAVE TO
MAY
MIGHT
SHOULD

17. CAN /
Mr. Johnson s car is not working. What _________
he do? SHOULD
CAN SHOULD MUST
Well, he __________________________________
call a mechanic.
CAN
COULD
MUST
HAVE TO
MAY
MIGHT
SHOULD

18. Exercises
Rewrite the sentences using the correct modal verb:
a) Is it possible for us to stay at home tonight?
Can we / Could we stay at home tonight?
_____________________________________________________________
b) I’m afraid I won’t give you permission to buy that.
I m afraid you can t / couldn t buy that.
_____________________________________________________________
c) I don’t have the ability to sing now, though I did when I was younger.
I can t sing now, though I could when I was younger.
_____________________________________________________________
d) I didn’t manage to contact you, no matter how hard I tried.
_____________________________________________________________
I couldn t contact you, no matter how hard I tried
e) If you come to stay it will be possible for us to visit all the sights.
_____________________________________________________________
If you come to stay, we can visit all the sights.

19. Exercises
Complete with must, mustn t, should / shouldn t
, don t have to:
1. "Do you want me to wait for you?" "No, it's OK. You
_______________________________ wait.
DON T HAVE TO
2. Tom gave me a letter to post. I __________________
SHOULD NOT
forget to post it.
DON T HAVE TO
3. You _______________ come if you don't want to but I
hope you will.
4. "What sort of house do you want to buy? Something
big?"
"Well, it _______________ be big - that's not important.
DOESN T HAVE TO
But it __________ have a nice garden - that's
MUST
essential."
DON T HAVE TO
5. We have enough food at home so we ____________
go shopping today.
MUST
6. This book is very valuable. You __________________
look after it very carefully and you __________ lose it.
MUSTN T