Important. Telling yourself or a child, or  a printed notice	 	
Polite reminder that someone is breaking a rule		
Describing a rule or procedure		

Actually, you're not supposed to smoke in here. 	We didn't need to buy any food as Dorothy brought loads. 	
Drivers must switch off their engines before refuelling.	We needn't have brought all that food as Dorothy had loads 	
I didn't have to get up early as I had the morning off. 	You have to wear a skirt. 	
I must remember to pay the electric bill. 	You must not accept lifts from strangers. Is that clear? 	
I needn't have got up early as the class was cancelled 	You should really try and get this finished before you go. 	
You're not supposed to wear jeans, but everyone does! 	You shouldn't have spoken to him like that. 	
I should have sent her a birthday card. 	You weren't supposed to tell them the price. 	
They were supposed to have finished last Friday. 	You're not allowed to wear jeans. 	
You're supposed to cross the road at pedestrian crossings but the police turn a blind eye.	You're not really supposed to wear jeans, I'm afraid.