So, in terms of practicing this weekend, I mentioned that instead of getting a problem-set today, what I am going to be posting is optional extra problems.

而对于这周的练习，我曾经说过今天将不会布置作业，但是会布置一些额外的习题。

麻省理工公开课 - 化学原理课程节选

And this should look kind of familiar to some of the problems you may have seen on the problem-set if you started it this weekend.

如果你们这周就开始做习题集的话,这样的题目你们,应该会觉得很熟悉。

麻省理工公开课 - 化学原理课程节选

- I mean that-- what began as, ah we'll do this this weekend turned out to be like a 100-hour project to revamp this whole thing.

我是说，这周末我们要做的是,改进整个工程，但这可能需要花100个小时。

哈佛公开课 - 计算机科学课程节选

I am so sad this weekend--it was Russian intellectual history.

这周末我真的很伤心,当时我选了俄国思想史

耶鲁公开课 - 欧洲文明课程节选