oil and fat refining

例句：

1. 1.The refinery is the heart of the oil industry.
   炼油厂是石油工业的核心。
2. 2. The process of refining oil involves removing impurities to produce clean fuel.
   提炼石油的过程包括去除杂质以生产清洁燃料。
3. 3. Refining techniques have improved significantly in recent years.
   近年来，提炼技术已经显著提高。