You mustn't be late for the test!
Everyone can enjoy the park.
You can get up later today... it's Sunday!
They know they mustn't leave rubbish in the park.
They know they must keep their park clean.
There are signs everywhere saying that teenagers can't ride skateboards or bikes.
We don't have to wear a uniform at school, thank God!
You don't have to pay to use the park...it's free!
it is allowed/possible
it is allowed
it is not allowed
it's not necessary
prohibition
it's not necessary
prohibition
obligation