单项选择题
A.聚氯乙烯 B.橡皮绝缘 C.非燃性橡套 D.丁基橡胶
A.400mm B.600mm C.800mm D.1500mm
A.15° B.20° C.25° D.30°
A.2m B.5m C.15m D.25m
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