refine

1. V-T When a substance is refined, it is made pure by having all other substances removed from it. 提炼[usu passive]

Oil is refined to remove naturally occurring impurities. 油经过提炼去除天然生成的杂质。

2. refiningN-UNCOUNT 提炼

...oil refining. …炼油。

3. V-T If something such as a process, theory, or machine is refined, it is improved by having small changes made to it. 完善[usu passive]

Surgical techniques are constantly being refined. 外科手术技术正在不断得到完善。