Has to (have to) / Must
Sometimes we can use ’must’ or ’has to’ to mean the same thing.
e.g. I need to get A in May’s class, so I must / have to participate a lot.
Generally, ’must’ is used for expressing personal feelings, and ’have to’ for expressing facts.
e.g. English is fun! You must love it! (duh!)
You have to turn off your mobile phone in all your English classes.
Every Thai student has to bring his / her dictionary to English class.
For negative statements and questions, we generally use ’do / does / did’ with ’have to’.
e.g. You don’t have to wear your uniform at your dormitory.
Katie doesn’t have to drive a car. She stays at the dorm.
Has to’ doesn’t provide choices. One cannot say ‘I can choose or not choose to do it.’ It basically means ‘No choice.’ You must do it!
CONCLUSION: ALL RULES, REGULATIONS, POLICIES are a MUST! You CANNOT break the rules because if you do, you will be called a deviant.