避雷器的作用？
参考答案：
限制作用于电气设备绝缘上的过电压值，以保护电气设备的绝缘。
No matter ____ he is, he must ____ and don't use his cell phones in the class. [ ]
A. what; obey the rules
B. who; obey the rules
C. that; obey the rule
D. where; obey the rule
聚乙烯聚丙烯扁条或类似机织物
