你不许在黑板上画画谢谢 那 youmust return the books in time ？你必须及时返还那些书you must not step the grass ?你不许踩草地you must put back the books after you have read them . you must not talk to drivers when the bus is moving . youmust cleanthe classroom every day. you mustnot jump the queue when you wait in line for the bus. you must put away the balls after you have used them. 这些那 ？帮帮我