In order to ensure normal teaching order, prote cting st ude nts ' healthy gr owth, e nsuring that national (property) is not lost, to preve nt or minimize t he occurrence of safety acci dent s, follow t he "prevent, re scue each other, e nsur e safety and re duce losses" pri nci ple, a ccor ding to t he local conditions, make the manag ement system. 1, the pri ncipal is the re sponsi bility of sc