1. A filter will remove most impurities found in water. 过滤器会滤掉水中的大部分杂质。
2. Oil is refined to remove naturally occurring impurities. 油经过提炼去除天然生成的杂质。
3. The air in the factory is filtered to remove impurities. 工厂里的空气经过过滤去除杂质。
4. Impurities were burnt away with the use of coke, producing a high-quality refined iron. 杂质用焦炭烧掉,产生高质量的炼铁。
5. Some people have attributed this longevity to their consumption of a natural mineral water, which is remarkably free from impurities. 一些人认为这些人长寿应归功于他们饮用的一种明显不含杂质的天然矿泉水。