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

Well, this whole business presents the problem I mentioned a moment ago.

这所有的内容都契合了,我刚才提到的问题

耶鲁公开课 - 古希腊历史简介课程节选