瓷绝缘表面做成波纹形，其目的是（）。
A、增加瓷绝缘强度
B、增加其抗弯强度
C、增加电弧爬距
D、防止尘埃落在绝缘上
参考答案：C
In my opinion, all Mr. Li ______ good to his students in his class at present. He is very strict with them in
their studies.[ ]
A. does does does
B. does do did
C. does does do
D. did do does
窃电者除应按所窃电量补交电费外，还应承担补交电费（）的违约使用电费。
A.3倍
B.4倍
C.5倍
D.6倍
