Occasionally, you'll find you need to cancel out units, because, of course, you're always doing unit analysis as you solve your problems, and sometimes you'll need to convert joules to kilogram meters square per second squared.

偶然地，你会发现需要消除单位，因为在解题时,经常要做单位分析，所以有时候需要把,焦耳换做,一千克乘以米的平方除以秒的平方。

麻省理工公开课 - 化学原理课程节选

And of course, there are still pollution problems with motorists.

当然，机动车的污染问题依然很严重。

我使用自行车 - SpeakingMax英语口语达人

So, don't forget to study this weekend and get those extra practice problems from the course website.

那么，这周末不要忘了复习,那些额外的习题可以在课程的网站上找到。

麻省理工公开课 - 化学原理课程节选

I'm very willing to talk to students about intellectual ideas, about course problems and so on.

我非常愿意同学生们一起讨论些好的想法,讨论下学习困难之类的话题

耶鲁公开课 - 心理学导论课程节选

Odds are if you're an upperclassman, you've had that experience where it's 12 AM, 1 AM, 2 AM, and you're really starting to stress over the incompletion of some problems that for some course, well frankly what this mechanism allows you to do if you're already 90 percent of the way there, you can call it a night and you can put it down and you could feel good nonetheless about where you got to.

对于上游的同学可能觉得无趣，因为他已经具备了这些经验，这时应该开始关注某些课程中,问题的不完整的部分，如果你已经学会了,里面90%的知识，你可以停工,或者把这门课扔到一边。

哈佛公开课 - 计算机科学课程节选