to back up

• 备用机场

  alternative airport

• 备用机车

  spare engine

• 备用电池

  standby battery

• 备用天线

  spare antenna

• 备用插座

  spare socket

• 备用设备

  standby facility

• 把...贮藏起来备用

  store as backup

• 留下备用

  stay on standby

• 留一辆卡车备用

  keep a lorry in reserve