A.2/5 B.1/2 C.1/4 D.1/3
A.圓周經(jīng)過(guò)原點(diǎn)的圓 B.圓周不經(jīng)過(guò)原點(diǎn)的圓 C.經(jīng)過(guò)原點(diǎn)的直線 D.不經(jīng)過(guò)原點(diǎn)的直線
A.三相故障 B.單相故障 C.跨線故障 D.所有故障