In Earth's earliest atmosphere, methane and carbon dioxide occurred at much higher levels than at present-a circumstance that was favorable for early life.(在地球最早的大气层中，甲烷和二氧化碳的含量比现在要高得多，这对早期生命来说是有利的。)
Although the system would consume energy, it would return energy to the grid via methane generation from composting nonedible parts of plants.(尽管该系统会消耗能源，但它会通过从植物不可食用的部分堆肥产生的沼气将能源回馈给电网。)
Many environmental experts now believe that methane is more responsible for global warming than carbon dioxide.(许多环境专家现在认为，甲烷比二氧化碳对全球变暖负有更大的责任。)
When our Sun later became hotter, the continued removal of atmospheric carbon dioxide and methane by early bacteria kept Earth's climate from becoming too hot to sustain life.(当我们的太阳后来温度变得更高时，早期细菌持续清除大气中的二氧化碳和甲烷，使地球的气候不至于变得太热而无法维持生命的存在。)
Therefore, the methane now emitted from open landfills should instead be burned to produce electricity.(因此，现在从露天垃圾填埋场排放的甲烷应该被用来发电。)
The large amount of methane contained in the atmosphere surrounding Neptune stained it blue.(围绕海王星的气层内所含大量甲烷将它染成了蓝色。)
Other ancient bacteria consumed methane, greatly reducing its amount in the atmosphere.(其他古代细菌消耗甲烷，大大减少了甲烷在大气中的含量。)
Methane and propane are alkanes.(甲烷和丙烷是烷烃。)
Far from the sun, in the outer solar system, beyond Jupiter's orbit, temperatures are low enough to permit ices to form out of water and out of gases like methane and carbon dioxide.(在远离太阳的外太阳系，在木星轨道之外，温度低到足以使冰从水以及甲烷和二氧化碳等气体中形成。)
The burning of methane generates carbon dioxide that is released into the atmosphere.(燃烧甲烷产生二氧化碳，然后释放到大气中。)
