back-up lamp

例句：

1. 1. The back-up lamp is essential for emergency situations.
   备用灯对于紧急情况至关重要。
2. 2. In the dark room, the back-up lamp provided enough light to read.
   在黑暗的房间中，备用灯提供了足够的光线来阅读。
3. 3.The company has a backup plan in case of power outages.
   公司有备用计划以防停电。