backrunadj.逆向的(反转的)backn.后面；背脊；靠背；后背；后卫vt.支持；后退adv.向后地adj.向后的；后面的；偏远的；过时的；积欠的back contact proving后接点检验backtracking program回溯程序back washing machine复洗机back satin gabardine缎背华达呢back to back sitting合背坐backspace subroutine返回子程序back-to-back tie背对背结住backscatter sounding后向散射探测back-up roll arbor组合支承辊的心轴back-bone material主体材料

back the oars倒着划浆