fuel such as coal or oil, that was formed over millions of years from the parts of dead animals or plants 化石燃料（如煤或石油） 
Carbon dioxide is produced in huge amounts when fossil fuels are burned. 化石燃料燃烧时会大量产生二氧化碳。 Fossil fuel reserves are rapidly being depleted. 化石燃料的储备正在迅速耗尽。 Gas is the only fossil fuel without environmental problems. 天然气是唯一没有环境问题的化石燃料。