(来学网)基牙右下5为第二类导线,应采用下列哪类卡环
  • A.
    (来学网)单臂卡环
  • B.
    (来学网)上返卡环
  • C.
    (来学网)下返卡环
  • D.
    (来学网)三臂卡环
  • E.
    (来学网)长臂卡环