Certainty: must/can't/couldn't

Date: 2015-10-07; view: 523.

Exercise 21. Complete the sentences with may/might/ could to express possibility in the past. Use the words in brackets.

Exercise 20. Rewrite these sentences. Use may/might/ could to express past possibility.

Example: They have left already.

They may/might/could have left already.

1. Mr. Smith went on business to France last night.

2. He has been working all day.

3. She didn't catch the 8 o'clock bus.

4. The secretary forgot about the meeting.

5. They left early.

Example: Where was Sally last night? — (she/be/at the cinema)

She may/might/could have been at the cinema.

1. She walked straight past me. (she/not see/me)

2. I can't find my purse anywhere. (I/leave/at home)

3. John is late. (he/miss/the train)

4. What was Peter doing yesterday? (he/work)

5. What has Sally had for breakfast? (she/have/bacon and eggs and a cup of tea) 6. What did that ear cost? (it/$5,000)

MUST/CAN'T/COULDN'T are used to express certainty about a present event.

MUST		BE/DO (Present Infinitive)/ BE ... -ING (Present Continuous Infinitive)
CAN'T	+
COULDN'T

MUST is used to say that we are sure about something the present.

There's a lot of noise from upstairs. It must be Tom. I meet her rather often. She must be living nearby.

CAN'T (not MUSTN'T/COULDN^' T) are used to say that we are sure that something is impossible.

Can I have some sweets? I'm hungry. You can't/couldn't be hungry. You've just had dinner!