till 2:00 in the morning. So they can't go to school at 7:00 in the morning."

VOA: standard.2010.02.24

You can't get what you want, till you know what you want."

汝欲得之,必先知之"

耶鲁公开课 - 博弈论课程节选

You won't have to solve it in this class, you can wait till you get to 18.03 to start solving these types of differential equations, and hopefully, you'll all want the pleasure of actually solving the Schrodinger equation at some point. So, just keep taking chemistry, 18 03 you'll already have had 18.03 by that point and you'll have the opportunity to do that.

你们不用在课堂上就解它，你们可以等到得到18，03之后,再开始解这些类型的微分方程，希望你们都想得到,实际解薛定谔方程的乐趣,所以，保持来上化学课，你们在那个点将会得到,你们有机会做到的。

麻省理工公开课 - 化学原理课程节选

And they often don't have to till at all, which is better for the soil.

VOA: standard.2010.04.15