甲烷（CH4）是大气中仅次于CO2对全球变暖贡献第二大的温室气体，全球大气CH4的收支取决于CH4的源与汇。

Next to CO2, methane (CH4) is the second important contributor to global warming in the atmosphere and global atmospheric CH4 budget depends on both CH4 sources and sinks.

youdao

A good example of that is CH4, because the CH bond is polar but symmetrically disposed in space.

甲烷就是一个很好的例子，因为极性键是,空间对称的。

麻省理工公开课 - 固态化学导论课程节选

And I picked looking at methane so we could see if there are other factors that we're not considering, that we need to maybe tweak our model a little bit, and I think we'll find that we do if we take a look at a polyatomic molecule, methane, CH4 so c h 4.

我选择甲烷这个例子，我们可以看到,如果有一些我们没有考虑到的因素，我们需要修改一下我们的模型，我们看一看,甲烷CH4这个多原子分子，就会知道这一点，甲烷。

麻省理工公开课 - 化学原理课程节选