煤层气的英文：
coalbed methane

Cattle release methane when they digest their food.
牛在消化食物时，会释放出甲烷。

I've never seen volcanoes of methane.
我从未见过甲烷火山。

What do we know about methane?
关于甲烷我们知道什么？

A bottom layer of nickel catalyst was provided to promote the endothermic reaction of steam and methane
底层镍催化剂促进蒸汽和甲烷的吸热反应。

Mixtures of 5-14% methane in air are explosive and have caused many mine disasters.
空气中若混有5～14%的甲烷就有爆炸的危险，已经造成了许多矿井灾难。