emergency power source

例句：

1. 1.The emergency power source is essential for the survival of the city.
   紧急电源对于城市的存活至关重要。
2. 2.The hospital had to rely on an emergency power source during the power outage.
   在停电期间，医院不得不依赖紧急电源。
3. 3.The generator was designed to provide an emergency power source in case of a power failure.
   发电机的设计是为了在电力故障时提供紧急电源。