煤是什么？为什么会引起疑问？

煤是什么？为什么会引起疑问？

煤的词义

煤，是一种由植物残骸在经过地质变化作用下形成的一种黑色的燃料。煤的主要成分是碳，同时含有氢、氧、氮和硫等元素。在全球能源消费中，煤是非常重要的一种化石燃料，被广泛应用于工业、发电、热力等领域。

煤引发的疑问

尽管煤在能源领域中有着如此重要的地位，但人们对于煤的认识却仍然存在很多关键的疑问。其中，最常见的疑问就是煤对环境的影响问题。由于煤的燃烧会释放出大量的二氧化碳、二氧化硫等有害气体，从而对大气和自然环境产生了极大的影响，最终影响到人们的健康和生活。

Bonus：十句包含coal英文句子

1. Coal is an important source of energy around the world.
2. Coal mining can be a dangerous and difficult job.
3. Coal-fired power plants are one of the primary sources of greenhouse gas emissions.
4. Coal is burned to generate heat and electricity.
5. Coal is a non-renewable resource and is expected to run out in the future.
6. The coal industry is facing increasing pressure to reduce its impact on the environment.
7. Coal is one of the cheapest energy sources available.
8. Coal can be converted into a liquid or gas fuel.
9. Coal power generation has been declining in many parts of the world due to the rise of renewable energy sources.
10. The use of coal in the United States has been declining for years due to the increasing use of natural gas.