A:oh,you_16_eat in the classroom B:i am sorry.i am a new student here.i donot know the_17_ A:it

A:oh,you_16_eat in the classroom B:i am sorry.i am a new student here.i donot know the_17_ A:it
doesnot mayyer._18_careful next time.
B:Can we eat in school?
A:you can eat _19_the dining room,but you canot eat in the classroom.
B:i see.Anything else?
A：you cannot arrive late_20_class.you canot listen _21_music in the classroom or hallway.
B:i remember now.Thanks