短語(yǔ)詞組短語(yǔ)back taper tap 倒錐絲錐back taper on diameter 倒錐back taper teeth 倒錐接合齒bidirectional back taper structure 雙倒扣the back taper raised dome 倒錐凸起圓蓋cavity with back taper opening 倒錐口型腔 返回 back taper