back seat (n.) back seat 后座back seam line [紡織科學技術]背縫線back seal test [機械工程]上密封試驗上彌縫實驗back seal 倒密封 回密封 背密封back scratcher 搔背器 后屈小腿挺身跳back scheduling [勞經] 反向安排日程;反向調度back scattering 反向散射 后向散射back scattered photon [醫(yī)藥科學]反向散射光子back scatter densimeter [土木建筑工程]同位素反射密度儀back scatter back scanner [交通運輸工程]后方障礙警報器back saw with plastic handle [經濟學]塑柄手鋸back saw 背鋸;背鑲金屬的鋸弓鋸;(鑲邊)手鋸back sand 背砂back salary 欠薪back run 封底焊;逆行;回流back row seat cushion [交通運輸工程]后座座墊back row pins [體育]后排球瓶后排柱群back rooms