unburned fuel

例句：

1. 1. The engine needs more unburned fuel to run smoothly.
   发动机需要更多的未燃烧燃料来顺畅运行。
2. 2.The pilot had to use unburned fuel from the tank to make up for the lost air.
   飞行员不得不使用油箱中的未燃烧燃料来弥补失去的空气。
3. 3.The research team found that unburned fuel could be a potential source of pollution.
   研究小组发现未燃烧的燃料可能是潜在的污染源。