a) We don't have to go to school on Saturdays.
b) I must be at school every day by 8:30 am.
c) You have to wake up early.
d) You mustn't swim alone in the lake.
a) We don't have to go to school on Saturdays.
b) I must be at school every day by 8:30 am.
c) You have to wake up early.
d) You mustn't swim alone in the lake.