The ability of coal to release a combustible gas has long been known.煤炭能够释放一种可燃性气体, 这早已为人所知。

I was desperate to change the subject, and we moved to less combustible talk about her future plans.我急切地想要转移话题, 于是我们开始谈论她对未来的打算, 这样气氛能缓和一些。