单项选择题
A.1Ω B.4Ω C.10Ω D.100Ω
A.避雷针 B.避雷线 C.避雷器 D.接地装置
A.1.5~2 B.2~3 C.1.5~3 D.2~4
A.200mm,300mm B.200mm,200mm C.300mm,300mm D.300mm,200mm
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