alkanes

例句：

1. 1. Alkanes are a type of hydrocarbon that consists solely of carbon and hydrogen atoms.
   烷烃是一种仅由碳和氢原子组成的烃类化合物。
2. 2.Alkanes play a crucial role in the production of plastics and other synthetic materials.
   烷烃在生产塑料和其他合成材料中起着至关重要的作用。
3. 3. Alkanes can be found in natural gas, which is a mixture of hydrocarbons.
   烷烃可以在天然气中找到，天然气是一种烃的混合物。