stand-by heat

例句：

1. 1. The generator is designed to provide stand-by heat during power outages.
   发电机设计为在停电期间提供备用热源。
2. 2.During a power failure, the stand-by heat can help maintain basic functions for several hours.
   在电力故障时，备用热源可以维持基本功能数小时。
3. 3. The engineers are monitoring the stand-by heat levels to ensure they are within safe limits.
   工程师正在监控备用热源水平，以确保它们处于安全范围内。