3. Logical assumptions and deductions
▪ Must:
▪ is used in affirmative sentences and expresses positive logical beliefs.
▪ To state something about which you are certain that is true.
6. Can’t and couldn’t
▪ Can’t and couldn’t are used in negations and express negative
logical assumptions.That is to say, you use them when you’re certain
that something is not true or real.
Monsters can’t be real!
10. Possibility
▪ Can + present infinitive expresses general possibility, something
theoretically possible.
You can have milk or juice.
11. Possibility
Could / may / might + present infinitive = It is possible/likely,
perhaps…
It is used to show that something is possible in a specific situation.
You should keep that number, it may be useful one day.
12. Possibility
Could / may / might + present infinitive = It is possible/likely,
perhaps…
NOTE: we can use can/could/might in questions, but not MAY.
Do you think you can/could/might give me an answer today?
13. Possibility
▪ Could / might / would + perfect infinitive
It refers to past possibility, something that was possible but didn’t
happen.
You might have changed jobs.
14. Needn’t + bare perfect infinitive
▪ It was not necessary to do something but, even so, it was done.
(You brought flowers even though
there’s plenty of them already)
You needn’t have brought
flowers!
16. Criticism
▪ Could / should / might / ought to + perfect infinitive are
used to criticise someone’s actions or lack of them in the past = it
would have been better if you had…
You could have been on time for the meeting.
18. Now it’s your turn!
Go to page 156 to complete
exercise 3.
19. Complete the sentences with the following modal
verbs forms and explain their meanings
Must have
Should have
Might have
Could have
Can’t have
Shouldn’t have
Might not have
Needn’t have
▪ That can’t have been John you saw
at the match – he’s out of the
country at the moment.
20. Complete the sentences with the following modal
verbs forms and explain their meanings
Must have
Should have
Might have
Could have
Can’t have
Shouldn’t have
Might not have
Needn’t have
▪ You needn’t have brought
sandwiches – there’s a perfectly
good cafeteria.
21. Complete the sentences with the following modal
verbs forms and explain their meanings
Must have
Should have
Might have
Could have
Can’t have
Shouldn’t have
Might not have
Needn’t have
▪ What a mess you’ve made!You
should have been more careful.
22. Complete the sentences with the following modal
verbs forms and explain their meanings
Must have
Should have
Might have
Could have
Can’t have
Shouldn’t have
Might not have
Needn’t have
▪ I don’t know why she didn’t ask me
how to do it – I could have easily
helped her.
23. Complete the sentences with the following modal
verbs forms and explain their meanings
Must have
Should have
Might have
Could have
Can’t have
Shouldn’t have
Might not have
Needn’t have
She must have thought you were too
busy – I can’t think of another reason.
24. Complete the sentences with the following modal
verbs forms and explain their meanings
Must have
Should have
Might have
Could have
Can’t have
Shouldn’t have
Might not have
Needn’t have
Martin really shouldn’t have
borrowed my tennis racket without
asking first.
25. Complete the sentences with the following modal
verbs forms and explain their meanings
Must have
Should have
Might have
Could have
Can’t have
Shouldn’t have
Might not have
Needn’t have
I don’t know why Fiona’s so late; do
you think she might have got lost
coming here?
26. Complete the sentences with the following modal
verbs forms and explain their meanings
Must have
Should have
Might have
Could have
Can’t have
Shouldn’t have
Might not have
Needn’t have
She might not have managed to find
the time to come.You know how
busy she is.
