Could you get me a glass of water?
You mustn't park your car here.
You have to wear a helmet when you drive a motorbike.
Mom is able to cook a full meal in 30 minutes!
She could run very fast when she was younger.
You may leave when you finish the test.
You ought to see a doctor.
We must wear uniforms at my school.
He could be in the library.
You don't need to do this excersice.
You needn't buy milk, we still have some.
You must be tired after all that work.
ABILITY
PERMISSION
ADVICE
POSSIBILITY
PAST ABILITY
NECESSITY
PROHIBITION
LACK OF NECESSITY
REQUEST
LACK OF OBLIGATION
CERTAINTY
OBLIGATION