A) My friends should help their parents. They should eat less sweet. They do not have to litter
b) My friends mustn't сross the road for a red traffic light. They must not skip school. They are must study.
c) My friends have to clean up their room when it's dirty. They have to follow the school rules. They have to brush their teeth.
d) My friends can swim. They can not fly. They can write off a remaster, like me