n.备份;备用品;后备计划;后备人员;
例句:
You can use a conventional heating system as back-up.
你可以用旧式的供暖系统作为备用。
A method for reliability analysis on back-up redundancy On cold fusion
冷备用冗余的可靠性分析方法
There is no emergency back-up immediately available
手头无法获得应急支持。