Backius巴基乌斯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 to the salt minesadv.又要辛苦了(返回工作岗位；重新工作)back-to school goods学生用商品back track programming回溯程序设计back pressure governor背压调节器back-level constancy黑色电平恒定性back ground correction本底校正back current principle逆电镰理back door interference后门干扰backing groove of weld焊缝反面坡口back temperature field背面温度场