短語詞組短語tooth back line 齒背線tooth back curve 齒背曲線;齒背曲線的tooth back of logarithmic spiral 對數(shù)螺線齒背tooth profile in back cone 背錐齒形back tooth 后臼齒;后牙Straight -back tooth 直線齒背刀齒Curved -back tooth 曲線齒背刀齒back of tooth [機]齒背back cone tooth profile [機]背錐齒廓 返回 tooth back