高频阻波器支柱绝缘子安装（支柱式）绝缘垫片厚度≤（）mm，位于绝缘子顶帽上，尺寸与顶帽一致。
A.2
B.3
C.4
D.5
参考答案：C
It was because I was caught in the traffic jam ________ I came to school late this morning.
A．which
B．when
C．what
D．that
善于治疗鼻渊头痛的药物是（）
A.羌活
B.辛夷
C.藁本
D.紫苏叶
E.荆芥
