Use must, have to, should, and their negatives to express different levels of obligation and advice.
Personal feeling of necessity. Example: I must finish this today.
Rules or circumstances require it. Example: I have to wear a uniform at work.
Recommendation, not strict obligation. Example: You should see a doctor.
Mustn't = it's forbidden. Don't have to = it's not necessary. Huge difference!
Recommendation, not strict obligation. Example: You should see a doctor.Mustn't = it's forbidden. Don't have to = it's not necessary. Huge difference!Personal feeling of necessity. Example: I must finish this today.Rules or circumstances require it. Example: I have to wear a uniform at work.