1N-VAR （物资、人员等的）支持，辅助Backup consists of extra equipment, resources, or people that you can get help or support from if necessary. （物资、人员等的）支持，辅助
There is no emergency back-up immediately available.
手头无法获得应急支持。
Alternative treatments can provide a useful back-up to conventional treatment.
替代疗法能为传统的治疗提供有效的辅助。
2N-VAR 备用品；后备计划 If you have something such as a second piece of equipment or set of plans as backup, you have arranged for them to be available for use in case the first one does not work. 备用品；后备计划
Every part of the system has a backup.
系统的每个部分都有备用元件。
Computer users should make regular back-up copies of their work.