Obligation
Which modal verbs do we use to express obligation?
Must and have to
Which modal verb do we use to express prohibition?
Mustn't or Can't
Which modal verbs express ability? and possibility?
can - could - be able to
may-might-could
Which modal verbs can we use to express certainty?
And to express possibilities?
must / can't
may/might/could
I _____ go alone tonight.
mustn't
(+) We _____ get up early on weekends if we make a commitment.
can
They are on a trip to England. Their house ____ be empty.
must
You don't had to behave like that in class yesterday.
You didn't have to behave like that in class yesterday.
Students _____ late to school. (arrive)
mustn't arrive
(-) You _____ be right! I always know the answers.
cannot
I ____ go to the cinema this afternoon, but today I'm ill.
could
Do she have to play the guitar at the concert?
Why must I rewrite this exercise last week?
What's the difference?
a) I did not need to flll my car tank.
b) I needn't have filled my car tank.
a) You didn't do that.
b) You did it anyway.
Which modals can I use to give permission?
Give an example!
can or may
I ___________ to complete the exam on time, I really tried hard!
I WAS ABLE to complete the exam on time, I really tried hard!
Put the words in the correct order:
pencil /that / have / can't / I / wrote /my / exam /with / been
That can't have been my exam, I wrote with pencil.
You needn't have to clean your room, I did it already.
You needn't have CLEANED your room, I did it already.
You should/ must go to the Uffizi when you're in Florence.
What's the difference?
should is for a recommendation
must for an obligation
Say this obligation in the past...
You must study for the test.
You have to study for the test.
Since I was a child I __________ swim very fast.
Since I was a child I HAVE BEEN ABLE TO swim very fast.
That student was not here last class. What could have happened?
He/She must have been ill.
He/She must have had no internet.
You ought go to the doctor as soon as possible.
You ought TO go to the doctor as soon as possible.
You SHOULD go to the doctor as soon as possible.