For a start, all animals, such as cows, pigs and sheep, always gas limed methane, which is the second most common green house gas after carbon dioxide.

首先，所有动物如牛、猪、羊都会排出甲烷气体，它是排在二氧化碳之后的第二大常见的温室效应气体。

For a start, all animals, such as cows, pigs and sheep, release a gas named methane, which is the second most common greenhouse gas after carbon dioxide.

首先，所有的动物，比如牛、猪和羊都会释放出一种叫甲烷的气体，这是第二常见的温室气体，仅次于二氧化碳。

Well, it turns out that about 78% of the air is actually made up of another common gas that honestly doesn't do much for our breathing at all, nitrogen.

事实证明，大约78%的空气其实是由另一种常见的气体组成的，不过说实话，这种气体对我们的呼吸根本没有什么作用，那就是氮气。