More than any other language I have encountered English caters for an amazing amount of expressions to order or strongly advise you to do something. Apart from the most obvious -must- and -have to- there are a few more:
In your opinion, something you should or should not do!
It is stronger than should, more generic (traditional)
This implies that there is a consequence if not followed through
Use must when it is an obligation/ order / based on rules affecting you personally
“Have to” is sometimes interchangeable with -must-. But it is less persuasive, more general.
You shouldn't say that it is impolite. (you are not supposed to say that)
You ought to go with her she can't do it alone. (you really need to go with her)
He'd better not come. (it is best if he does not come it could mean trouble otherwise)
You must take care of yourself. (if you do not take care of yourself who does?)
You have to follow the guidance of the headmaster. (It is the guidance you should follow, but will you?)
Try it yourself
Please find below the link to the exercise and the document itself for downloading directly: http://wix.to/VcANC-0
If you want to learn more about when to use which verb and in which context, book a lesson and we will practise it together.