LET'S LEARN AND WRITE IN ENGLISH



must/ mustn't/ don't have to



Obligation
Prohibition
No obligation
I / you
Must
Mustn’t
Don’t have to
He/ she/ it
Must
Mustn’t
Doesn’t have to
We/ you/ they
Must
Mustn’t
Don’t have to

a. Use
 
  I must go to school → correct
  I must to go school → not correct
 She mustn’t smoke  → correct 
  She  mustn't  to smoke → not correct
  She  doesn't have to go to school today

b.     Meaning:


meaning
must
You are obliged to do something/it is necessary → obligation
Mustn’t
There is no choice/ you are prohibited from doing something
→ prohibition
Don’t have to
There is a choice/ you have options/ you can do something, but you are not obliged to do it