(来学网)由颊、舌两个相对的卡环臂及近远中边缘支托(或横贯式支托)组成的卡环是
  • A.
    (来学网)正型卡环
  • B.
    (来学网)对半卡环
  • C.
    (来学网)应力中断式卡环
  • D.
    (来学网)长臂卡环
  • E.
    (来学网)间隙卡环