And then we calculate changes, the convention is understood with respect to what is the zero, right.

然后我们计算改变,这个约定就是用来规定零点的位置的。

麻省理工公开课 - 热力学与动力学课程节选

And then I think it looks like most people understood that four was not a possibility.

然后我认为,大多数人是理解第4个选项,是不可能。

麻省理工公开课 - 化学原理课程节选

So, practitioners who understood what we would know to be chemistry were highly valued in that society. And then, you may expand it to other chemical processes, dyeing of cloth, glassmaking, and metals extraction.

所以，理解我们所知为化学的,先行者们，在那个社会是,非常宝贵的，当时，你可能将其扩展到另一个化学过程，如布料的染色，玻璃的制造，还有金属提取。

麻省理工公开课 - 固态化学导论课程节选

And once he did that, both he and many other scientists, could then, once they understood what caused the fluorescence, make little changes to the actual protein, and tune what the properties of that fluorescent protein were.

而且一旦他做成了这个，一旦他们弄清楚了是什么导致萤光，他和其它很多科学家，就可以对蛋白质做微小的改变，调节蛋白质的荧光性质。

麻省理工公开课 - 化学原理课程节选