can/can't/have to/don't have to/mustn't WW2

Juan’s mum says he ___ go to bed now – it’s really late! 

You ___ drop litter – it’s against the law. 

Do you really ___ leave now? It’s still quite early.

Piotr ___ buy a ticket for the concert – he’s already got one.

You ___ play near busy roads – it’s dangerous.

I can’t stay too late. My parents say that I ___ be back home by 9.30.