low grade fuel

例句：

1. 1. The car needs a newengine to run efficiently.
   这辆车需要一个新的引擎才能高效运行。
2. 2. The old car is runningon low grade fuel.
   旧车正在使用低等级燃料。
3. 3. The company switched to using lowgrade fuel for its fleet of trucks.
   该公司将其车队的卡车更换为使用低等级燃料。