hello please i want you explain what is certainity and necessity models and what is the difference between have to, and must
had better i hope you answer me soon i have no time
with due great to all teachers here
may Allah bless you efforts
"Must" has a stronger obligation than "Have to".
For example you say, I have to go! It means you want to go, maybe you have some works to do, or you don't have any works and you just like to go.
But when you say, I must go, it means there is something that makes you to go. Maybe you have an urgent job to do, you have a class, the rule of the place dose not let you to stay there, or etc.