It's one of the only compounds, there's only I think three, where the density actually goes down when it freezes.

它是我见过的，唯一一个，在降温时密度下降的化合物。

麻省理工公开课 - 固态化学导论课程节选

Maybe you're not looking at a reaction, but you've got some new compound, and you're looking at it go from liquid to solid or to gas.

也许你研究的不是一个反应,但你得到了一种新的化合物,你看着它从液体变成了固体或气体。

麻省理工公开课 - 热力学与动力学课程节选

And when a compound is decomposed, the atoms are recovered unchanged.

当一个化合物被分解的时候，原子有恢复原来未曾改变的面貌。

麻省理工公开课 - 固态化学导论课程节选

So, a natural product is something that is made by nature, and often natural products, whether it comes from a plant or a marine organism have some really good, useful properties. And so, one particular compound has anti-tumor properties. So, again, along this line of cancer research.

天然产物是在自然界中生成的,通常一个天然产物，不管是来自植物或者海洋生物,都有些非常好非常实用的性质，其中的一个特殊的化合物,可以治疗癌症,再一次我们又来到癌症研究上。

麻省理工公开课 - 化学原理课程节选