This document discusses the uses of modal verbs in English. Modal verbs are used to indicate modality, or possibility, ability, permission, obligation, and advice. The document lists common modal verbs like can, may, must, should and their meanings. It provides examples of how modal verbs are used to express probability, permission, ability, obligation, possibility, advice and prohibition.

1. Modals With Perfect

3. You may go home now!
modals

4. SO WHAT IS MODALS?
A modal verb (also modal, modal auxiliary verb, modal
auxiliary) is a type of auxiliary verb that is used to
indicate modality
From wikipedia

5. USES OF MODALS
Probability
Permission
Ability
Obligation
Possibility
Advice
Prohibition

6. Modal Verb
Meaning
Expressing
Example
to have to
100 % obligation
I must stop when the traffic
lights turn red.
to be very probable
logical conclusion
(deduction)
He must be very tired after
such enormous work
not to be allowed to
prohibition
You must not smoke in the
hospital.
to be able to
ability
I can swim
to be allowed to
permission
Can I use your phone please?
it is possible
possibility
Smoking can cause cancer !
to be able to
ability in the past
When I was younger I could
stay up all night and not get
tired..
to be allowed to
more polite permission
Excuse me, could I just say
something?
it is possible
possibility
It could rain tomorrow!
to be allowed to
permission
May I use your phone please?
it is possible, probable
possibility, probability
It may rain tomorrow!
must
must not
can
could
may

7. to be allowed to
might
need
it is possible, probable
necessary
not necessary
need not
more polite permission
Might I use your phone
please?
weak possibility, probability I might come and visit you in
America next year, if I can
save enough money.
necessity
Need I say more?
lack of necessity/absence of I need not buy any tomatoes.
obligation
There are plenty in the
fridge.
used to say or ask what is the
correct or best thing to do
had better
I should / ought to see a
doctor. I have a terrible
headache.
to suggest an action or to
show that it is necessary
advice
You should / ought to revise
your lessons
to be very probable
should/ought to
50 % obligation
logical conclusion
(deduction)
He should / ought to be very
tired after such enormous
work
to suggest an action or to
show that it is necessary
advice
You 'd better revise your
lessons

8. Example :
Tia fails to pass the exam, she should have studied hard