单项选择题
A.气焊 B.电阻焊 C.钎焊 D.电弧焊
A.0.10~0.15m B.0.15~0.20m C.1.2m D.1.25m E.1.3m
A.0.1MΩ B.0.5MΩ C.2MΩ D.20MΩ