It's just taken out of the reading of lecture notes.

只需要记录下阅读文献的号码就行。

麻省理工公开课 - 固态化学导论课程节选

Generally we call... classes our... like the actual classes you take, and courses are our majors.

一般情况下我们会说编号……号码就代表了我们上的课，课程就是我们的专业。

MIT用数字说话 - SpeakingMax英语口语达人

W" And after the numeral, put a "w".

那就在你的号码后写一个。

麻省理工公开课 - 电影哲学课程节选

It's like you have a social security number or other ID number, which positively--there might be another person with the same name as you, God forbid, but you at least have your own number, which is guaranteed to be unique to you.

就好比社保号,或者其他身份号码,很有可能,有另外一个人,和你重名,希望这不要发生,但你至少有唯一的识别号,用于区分自己和他人

耶鲁公开课 - 金融市场课程节选

So, I said, okay, I didn't want to assume so we clicked senior and frankly it was then a dead end because apparently to get some senior discount you need to have some special pass or something like this that we didn't have and yet that certainly wasn't obvious here so now we together and this person in particular had to figure out how you go back and then restart this process.

我说，好的，我不希望揣测，所以我点击了老人票,然后问题就来了，因为似乎,需要特殊的号码之类的东西来购买老年票,但是我们没有,明显我们不应该走这步,现在我们一起必须找出,怎样返回，然后重新开始这个步骤。

哈佛公开课 - 计算机科学课程节选