The inventor Henry Bessemer discovered that directing a blast of air at melted iron in a furnace would burn out the impurities that made the iron brittle.
发明家亨利·贝塞默发现，在熔炉里对铁水直接吹一吹气，就会烧掉使铁变脆的杂质。
2
Factories that burn coal still polluted the air with a lot of black smoke.
烧煤的工厂仍然产生大量的黑烟污染空气。
3
Wind turbines do not burn oil or coal and do not pollute the air.