backupsn.备份
backupn.后备
backup of each other互为备用性
backup roll extractor支承辊换辊装置
Backup Bus Controller备份总线控制器
Backup Flight Control备用飞行控制
backup instrumentation备用检测仪器
backup yaw damper unit备用偏航阻尼器
backup tape generation备份磁带生成
backup power indicator后备电源指示灯