It can’t be changed now.

6 'What's Linda doing?' 'I'm not sure.' (she may / watch / television)

She may be watching television.

7 Ann was standing outside the cinema. (she must / wait / for somebody)

She must have been waiting for somebody.

8 He was in prison at the time that the crime was committed, so (he couldn't / do / it).

He couldn‘t have done it.

9 Why weren't you here earlier? (you ought / be / here, earlier)

You ought to have been here ealier.

10 Why didn't you ask me to help you? (I would / help / you)

I would have helped you.

11 I'm surprised nobody told you that the road was very dangerous. (you should / warn)

You should have been warned.

12 George was in a strange mood yesterday. (he might not / feel / very well)

He might not have been feeling very well./He might not have felt very well.

5 Rewrite each sentence using the word given in brackets.

1 I don't think we left the keys at home. (can't)

We can’t have left the keys at home.

2 Perhaps they sold their house. (might)

They might have sold their house.

3 Perhaps she caught a later train. (may)

She may have caught a later train.

4 I suppose it's possible that he took the wrong turning. (could)

He could have taken a wrong turning.

5 I reckon he stole it. (must)

He must have stolen it.

6 Perhaps she has told him by now. (may)

She may have told him by now.

7 Knowing him, he probably broke it. (bound to)

He is bound to have broken it.

8 It was possible for it to explode. (could)

It could have exploded.

9 Why didn't you invite me to your party! (might)

You might have invited me to your party!

10 I don't think he was a very good driver, in that case. (couldn't)

He couldn´t have been a very good driver.

11 I'm fairly sure that they threw it away. (must)

They must have thrown it away.

12 It's possible they had already done it. (may)

They may have already done it.

13 You were lucky they didn't kill you! (might)

They might have killed you./You might have been killed.

14 Perhaps she didn't know about it. (may not)

She may not have known about it.

15 I think he was drunk. (must)

He must have been drunk.

6 Put each sentence into the Past.

1 Sorry, but I have to leave early.

I had to leave early.

2 But I'm sure you must know the answer.

You must have known the answer.

3 I think you should tell him the answer.

You should have told him the answer.

4 You need to leave me the keys.

You needed to leave me the keys.

5 He's got to come here at once.

He had to come here at once.

6 You shouldn't be so impatient.

You shouldn´t have been so impatient.

7 He must be her new boyfriend.

He must have been her new boyfriend.

8 She ought to see him immediately.

She ought to have seen him immediately.

9 He must not let the dog into his bedroom!

He shouldn´t have let the dog into his bedroom!

10 You might try to be a little more friendly!

You might have tried to be a little more friendly!

7 Some modal verbs have different implications, especially when referring to past events. Match the sentences on the left to the implied meanings on the right (in italics).

1 I should have given her my phone number. I didn't give her the number.

2 I had to give her my phone number. I gave her the number.

3 I didn't have to give her my phone number. I didn't give her the number.

4 She wouldn't let me give her my phone number. I didn't give her the number.

a He can't have gone to hospital. I'm sure he didn't go.

b He couldn't go to hospital. He didn't go, because he wasn't able to.

c He must have gone to hospital. I'm convinced he has gone.

d He needn't have gone to hospital. He went, but it was unnecessary to.

e He shouldn't have gone to hospital. He went, but it was a mistake to do so.