Please maintain discipline in Class.或者Keep order in class,please.但用祈使句表达都不符合题意,用被动语态更好.
discipline must be maitained (或obeyed) in class!
英语翻译汉译英：上课必须遵守纪律.
Please maintain discipline in Class.或者Keep order in class,please.但用祈使句表达都不符合题意,用被动语态更好.
discipline must be maitained (或obeyed) in class!