review the rules for using modals for speculation and deduction

1. PRESENT AND
PAST
SPECULATION
MODAL VERBS

2. PRESENT PAST
MODAL +
INFINITIVE
MODAL +
HAVE +
PAST
PARTICIPLE

3. MUST
• To express a strong belief
that something is true
• E.g. John MUST BE happy to
see us . (present)
• John MUST HAVE LOST his
mobile phone.( Past)

4. MIGHT, MAY , COULD
• When we think that it is possible
that something is true
• E.g. The lions
MIGHT/MAY/COULD BE hungry
now. (present)
• E.g. Lucy MIGHT/MAY/COULD
HAVE MISSED the train. (past

5. CAN`T
• When we have a strong belief that
something is not true.
• E.g. It CAN`T BE a domestic cat.
It`s too big. (present)
• E.g. Peter CAN`T HAVE LEFT.
His car is outside his house. (past)

6. WE USE
MODAL + BE+V-ING
TO SHOW THAT SOMETHING
IS POSSIBLE IN PRESENT BUT
NOT CERTAIN.
e.g. Mary MIGHT BE WORKING
at home today. (Perhaps she is
working at home , I`m not sure.)

7. WE USE MODAL + HAVE BEEN +
V-ING
TO MAKE LOGICAL
DEDUCTIONS ABOUT AN
ACTIVITY IN PROGRESS IN
THE PAST.
e.g. He passed an exam easily. He
MUST HAVE BEEN REVISING
for weeks.

10. 1 There's no reply.
He__________ be out.
1. can
2. must
3. can't
4. mustn't
MUST

11. 2 I've got no idea where she is.
Try the library.
She____________ be in there.
1. might
2. can't
3. must
4. will
MIGHT

12. 3 You ________________
left it in the office, I suppose.
1. could have
2. might have
3. must have
4. I and 2 are both possible
I and 2 are both possible

13. 4 They _____________ got in
through the window - it's on
the 21st floor!
1. can have
2. must have
3. can't have
4. might have
CAN`T HAVE

14. 5 Judging by the present evidence,
we think he ________________
used a disguise.
1. might have
2. probably
3. might
4. 1 and 2 are both possible
1 and 2 are both possible

15. 6 They _____________ got there
already. They only left ten minutes
ago.
1. can't
2. must
3. must have
4. can't have
CAN`T have