A.點(diǎn)劃線(xiàn) B.雙點(diǎn)劃線(xiàn) C.虛線(xiàn) D.細(xì)實(shí)線(xiàn)
A.100~150mm B.150~200mm C.200~250mm D.250~300mm
A.電流不當(dāng) B.間隙不當(dāng) C.電弧過(guò)短 D.電弧過(guò)長(zhǎng)