短語詞組短語back filled sand 回填砂peeling back of sand cores 砂芯脫殼back -up sand 填Drop -back sand unit 落砂單元and back filling sea sand 海砂回填oil no -back sand mold 油改性樹脂自硬砂型sand back 沙丘Fred sand back 弗雷德 返回 back sand