And this is the same periodic table that you're going to get in your exams, so it's good to practice doing your problem-sets with that periodic table so you're not relying on having the double check right there of seeing what the electron configuration is.

这也是你们考试时会用到的相同的表,这样你们就不会，所以使用周期表来做问题集,是很好的练习,这样你们就,不会依赖于再次确认,电子构型是什么了。

麻省理工公开课 - 化学原理课程节选

Now, in practice, it depends on how good your measurement is.

在实践中，它取决于你的测量方法有多高明。

麻省理工公开课 - 热力学与动力学课程节选

Oftentimes, inventions that seem, in the abstract, to be good ideas may be impossible because something that you have to do to make it actually come into practice is too expensive and so it's not economic to produce the invention.

通常在理论上,创新固然不错,但却很难实现,因为把创意变成现实,花费会相当的昂贵,实现这样的创意非常不合算

耶鲁公开课 - 金融市场课程节选