USES

USES

ABILITY

CanCould (past)

POSSIBILITY

Can

(general or theoretical )Could

MayMight

(less probablethan may)

PERMISSION

Can

May

(formal)

REQUEST

Can /

Could

Will

(formal)May

(formal)Would

(formal)

OBLIGATION

Must

(imposed by the speaker)Have to

LACK OF OBLIGATIONDont have toNeednt

DEDUCTION /

CONCLUSIONMustShould

(less certain)

Cant

PROHIBITION

MustntCantMay not

ADVICEShould

Ought toMight

Could

OFFERShall

Would

SUGGESTION

Shall

WouldShould

(formal)

EXAMPLES

USE

1.She can drive a lorry

_______________________

2.You dont have to get up early on Saturday

_______________________

3.Look at the snow; it must be cold outside.

_______________________

4.You mustnt smoke here.

_______________________

5.I might get a job soon

_______________________

6.Shall we go to the theatre this evening?

_______________________

7.Will you please help me with my homework this afternoon?

_______________________

8.You have to be at school at 8:45.

_______________________

9.If you want to pass English, you should study hard

_______________________ 10. Helen hasnt come to school since Monday. She must be ill _______________________

11.Can you take me to the bus station?

_______________________

12.You may only use a pen during the exam

_______________________

13. I had to go to school very early when I was in England

_______________________ 14.It may not rain again this winter

_______________________ 15.Its very cold outside; you ought to wear a coat.

_______________________

MODAL PERFECTS MODAL+HAVE+PAST PARTICIPLE refers to the past

MAY HAVE / MIGHT HAVE (positive and negative) possibility in the past: It is possible that something happened or didnt happen in the past.

- You may have lost your keys at work (= perhaps you left them at work.)

- They might not have heard the news (= maybe they didnt hear the news.)

COULD HAVE suggests an alternative in the past: an opportunity that we didnt take or a possible result that didnt happen.

- We could have gone somewhere but we were too tired.

- You were lucky. You could have caused an accident.

MUST HAVE Deductions about the past. We are sure that something happened or we see it as logically true.

- My watch says its only ten past five. It must have stopped.

- The lights were on. He must have been at home (= Im sure he was at home.)

CANT / COULDNT HAVE impossibility in the past : we are sure that something didnt happen or we see it as logically impossible.

- He only spent five minutes in the job. He couldnt have done it properly (= its impossible that he did it properly.)

SHOULD HAVE / OUGHT TO HAVE unfulfilled obligation in the past : we were expected to do something but we didnt or we were advised to do something but we didnt follow the advice.

- He hurt her feelings. He should have talked to her (= he was expected to do it but he didnt.)

- You failed the history test. You ought to have studied harder (= I advised you to do it but you didnt.)

SHOULDNT HAVE / OUGHT NOT TO HAVE criticism of a past action : something wasnt the best thing to do but we did it or we were advised not to do something but we did it anyway.

- He hurt her feelings. He shouldnt have said such cruel words to her (= it was not the best thing to do.)

- You failed the history test. You shouldnt have been so confident that you would pass (= I advised you not to be so confident but you were.)

NEEDNT HAVE lack of obligation : something that we did but later we realised it was unnecessary.

- After driving at top speed, Laura arrived half and hour early. She neednt have hurried.PRACTICE: Rewrite the underlined sentences using modal perfects so that they mean the same.

1. Im sure David didnt forget about the party. I reminded him this morning.

David couldnt ___________________________________________________________________________________________________

2. Im sure that something delayed him.

Something _____________________________________________________________________________________________________3. Perhaps the missing girl ran away from home.The missing girl _________________________________________________________________________________________________

4. The computer didnt make a mistake. Thats impossible.The computer___________________________________________________________________________________________________

5. Its possible that the thief had a key.The thief_______________________________________________________________________________________________________

6. Theres a parcel outside. Im sure the postman left it.The postman ___________________________________________________________________________________________________

7. Im sure he was English.He____________________________________________________________________________________________________________

8. We advised her not to be late for her job interview but she was.She ___________________________________________________________________________________________________________

9. When he went out, we recommended him to lock the door but he didnt.He ___________________________________________________________________________________________________________

10. Its impossible that John pressed the right button.

John __________________________________________________________________________________________________________

11. Maybe Phil missed the train.

Phil ___________________________________________________________________________________________________________

12. We paid the waiter but it was a waste of money because service was included in the bill.

We____________________________________________________________________________________________________________

13. Its possible that the driver didnt see the warning sign.

The driver ______________________________________________________________________________________________________

14. We left early but it was unnecessary because we have done the journey much more quickly than I expected.

We____________________________________________________________________________________________________________

15. We had the chance to buy the car but in the end we decided not to buy it.

We ___________________________________________________________________________________________________________

16. Perhaps 16. John lost his way. It isnt very easy to find this place.

John __________________________________________________________________________________________________________