COULD - POSSIBILITY
CAN - ABILITY
CAN'T - IMPOSSIBILITY
COULDN'T - ABILITY
SHOULD - ADVICE
COULDN'T - POSSIBILITY
COULD - ABILITY
CAN - PERMISSION
CAN'T - ABILITY
CAN - POSSIBILITY
SHOULDN'T - ADVICE
MUST - OBLIGATION
MUSTN'T - PROHIBITION
CAN'T PERMISSION
I could swim when I was 10.
I can lend you a pen. I have a lot.
He can't drive
She couldn't walk when she was a baby.
We could bake a cake because we had all the ingredients.
Students should do some sport
You shouldn't eat so much candy.
People mustn't smoke in public places.
We can't phone Mary. We haven't got her phone number
They couldn't enter because the door was locked.
You can't go out of the classroom during the exam.
Sara can speak four languages
You must wear trainers for PE lessons.
It's hot in here. Can I open the window?