A.直徑10mm,長350mm的鋼棒,端部應磨圓B.直徑12mm,長350mm 的鋼棒,端部應平整C.直徑10mm,長350mm的鋼棒,端部應平整D.直徑12mm,長350mm的鋼棒,端部應磨圓
A.10mmB.15mmC.20mmD.30mm
A.46.7B.46.6C.46.5D.46.4