Question

. «You (to know)_______________
that children under the age of sixteen (not to allow)_________________
in here? You (to see)_________________the notice on the door?»

Answer 1

Do you know that children under the age of sixteen are not allowe in here? 

Do you see the notice on the door

Answer 2

Don't you know that children under 16 are not allowed in here? Haven't you seen the notice on the door?