Complete the sentences with mustn't or needn't
You.. stay up late- you've got school tomorrow morning.
We ... leave the door open- Kate has got a key
You ... write to your parents about this - I've already written to them
You ... ride your bike so fast- we've got plenty of time
You.. stay up late to learn this poem- I'll learn in the morning.
We... leave the door open- the rain will come in
You.. write to Ann about this - if you do, she'll tell everybody
You.. ride your bike so fast- the road is wet