preheat train in distillation unit

例句：

1. 1. Before we start the project,we need to preheat the furnace.
   在我们开始这个项目之前，我们需要预热炉子。
2. 2.The chef preheated the pan beforeadding the ingredients.
   厨师在加入食材前预热了锅。
3. 3. The car needs to bepreheated before taking off.
   汽车在起飞前需要预热。