短語詞組短語back of tooth [機]齒背;齒背back cone tooth profile [機]背錐齒廓angle of back of tooth 齒后角Back Of A Tooth 齒背Straight -back tooth 直線齒背刀齒Curved -back tooth 曲線齒背刀齒tooth back [機]齒背tooth back line 齒背線tooth back curve 齒背曲線;齒背曲線的 返回 back tooth