短语词组短语back of tooth [机]齿背;齿背back cone tooth profile [机]背锥齿廓angle of back of tooth 齿后角Back Of A Tooth 齿背Straight -back tooth 直线齿背刀齿Curved -back tooth 曲线齿背刀齿tooth back [机]齿背tooth back line 齿背线tooth back curve 齿背曲线;齿背曲线的 返回 back tooth