You should wash your clothes after one use.
Advice
You must wash with cold water. Says the label.
Obligation
You must use the iron to iron your clothes.
Obligation
You must not mix electronics and water.
Phohibition
You should set an alarm off to be on time for class.
Advice
You shouldn´t eat without washing your hands first.
Advice
You must not wash it with hot water.
Prohibition