1.You can't draw on the blackboard.
- Don't draw on the blackboard.
2.You must stand in line to wait for a bus.
- Stand in line to wait for a bus.
3.You can't wear a hat in class.
- Don't wear a hat in class.
4.You can eat in the dining hall.
-- Eat in the dining hall,(please)
5.You can wear a uniform ata school.
--Wear a uniform ata school(,please)