This document discusses English modal verbs and their uses for expressing ability, certainty, obligation, expectations, advice, deductions about the past, and necessity. It explains the differences between modal verbs like can and be able to, must and have to, may and might, should and ought to, must have and can't have, as well as forms like had better, was/were to be, needn't have, and didn't need to. Examples are provided to illustrate the proper context and usage of each modal verb.

2. 1. Present and future
2. Past
3. Exercises

3. 1.ABILITY: Can and Be able to
-Can: ability
Ex: I can swim.
-Be able to is used in situations where can does not
have the necessary grammatical form.
Ex: I’d like to be able to swim.

4. 2. CERTAINTY and UNCERTAINTY:
-Must and can’t: make deductions, when we are more
and less certain about something.
Ex: You must be tired after your journey .(I suppose you
are)
That can’t be Sue. She’s in Brazil. (I’m sure it’s
impossible)
-May and might: express uncertainty or possibility.
Might is less likely than may.
Ex: It may not rain. I might go out. I don’t know.

5. 2. CERTAINTY and UNCERTAINTY:
-Be bound to: refers to the future, whereas must refers
to the present.
Ex: You’re bound to see Paula if you go there.
You must see Paula if you go there.

6. 3.OBLIGATION:
-Must and have to:
+Have to: describes obligations made by someone else.
Ex: you have to turn left here. (It’s the law)
+Must: a personal obligation.
Ex: You must start working harder! ( I say so)

7. 3.OBLIGATION:
-Mustn’t and don’t have to:
+Mustn’t: describes something which is not allowed.
Ex: You mustn’t leaves any bags here. (It’s against the rules)
+Don’t have to: something which is not necessary.
Ex: You don’t have to apply yet. (It’s not necessary)
- Should and ought to: have the same meaning; describe
‘what is good idea’ and can be used to give advice, or polite
instructions.
Ex: I think you should see a doctor.
You ought not to continue.

8. -Should: describes actions we expected to
happen.
Ex: Brenda should be home by now. (She is
expected to be)
-Is/ Are to: used in formal instructions.
Ex: No-one is to leave the room.
You are not to leave the room.

9. -Had better: refers present or future time and
give advice how to stop something going wrong.
Ex: I think you’d better leave now. (before it’s too
late)
You’d better not drive. (It’ might be
dangerous)

10. - Could: describes past ability
Ex: When I was young, I could run very
fast.

11. - Could and Was able to
Was able to describes the ability to
successfully complete an action
Ex: Mary was able to help us. (She
actually helped us)
Mary could help us. (But perhaps she
didn’t)

12. -Must have and Can’t have: used to make deductions about
past actions.The “have” form does not change.
Ex: I must have left my wallet in the car. (I am sure I did).
Jim can’t have noticed you. (I am sure he didn’t).

13. - May have, Might have and Could have: express
possibility or uncertainty about past actions.The “have” form
does not change.
Ex: Jean might have missed the train. (Perhaps she did)
He may not have received the letter. (Perhaps he didn’t)
You could have been killed! (It was a possibility)

14. - Was/Were to be: describes something which was supposed
to happen, but didn’t. It is formal in use. The “have” form
does not change.
Ex: He was to have left yesterday.
(He was supposed to leave, but he didn’t)

15. - Had to
Had to is generally used as the past form of must
Ex: Sorry I’m late, I had to take the children to school.
The question form is Did you have to?
Ex: Did you have to work late yesterday?
- Should have or Ought to have
These express the speaker’s feeling that a mistake was made. The
“have” form does not change.
Ex: You should have posted the letter yesterday.
(You made a mistake)
You shouldn’t have told me the answer.
(You were wrong)

16. - Needn’t have or Didn’t need to
Needn’t have describes an action which happened, but was
unnecessary. The “have” form does not change.
Ex: I needn’t have bought more sugar.
(I did, but we have enough)
I didn’t need to buy more sugar.
(I didn’t, because we had enough)