Can/Could
You ______ drink more water if you want to stay healthy.
should
When I was five, I ______ read simple books.
could
My brother ______ play the piano very well.
can
You ______ smoke in the hospital. It’s prohibited.
must not
Visitors ______ show their ID before entering the building.
must / have to
Students ______ wear uniforms at this school. It is a rule.
must / have to
If you want to pass the exam, you ______ study harder.
should / ought to
When she was younger, she ______ run very fast.
could
I’m not sure, but they ______ come to the party tonight.
might / may
You ______ talk loudly in the library.
must not / shouldn’t
______ I open the window? It’s very hot in here.
may / can
I ______ help you with your homework if you want.
will / can
We ______ leave now or we will miss the bus.
must
You ______ worry so much. Everything will be fine.
shouldn’t
I ______ like to ask you a question.
would
You ______ finish this report today. It’s urgent.
need to/ must
I ______ buy a new notebook because I found my old one later.
needn’t have bought
You ______ bring food to the party. We already ordered pizza.
needn’t bring
I bought extra tickets, but I ______ them because many people didn’t come.
needn’t have bought
I ______ wake up early tomorrow for work.
have to
She ______ cooked dinner. We decided to eat at a restaurant.
needn’t have cooked
The lights are off. They ______ left already.
must have left
He looks very tired. He ______ worked all night.
must have worked
I bought extra tickets, but I ______ them because many people didn’t come.
needn’t have bought
You ______ come tomorrow if you are busy.
don’t have to