如果需要的话，你可以在跑步机上跑步。但如果可以的话，最好一个礼拜可以在户外跑一两天。

You can do these runs on a treadmill if necessary, but it would be ideal if you could run outdoors one or two days a week.

youdao

正如我在《儿女满堂的自私原因》中笑谈：“没有人要求降生，但如果可以要求的话，几乎所有人都希望这样。”

As I quip in Selfish Reasons to Have More Kids, "No one asks to be born, but almost everyone would if he could."

youdao

我们知道，若同样的时间可以赚10美元，我们不必在意所用时间到底值不值，但如果可以赚100美元，我们的时间成本就高了。

We accept that it’s not worth our time to worry about $10, but when it’s $100, we get cheap again.

youdao

I have it on reserve, but that's not required for the mid-term; it's just if you're interested in seeing it.

我将其列为推荐书目,但不作为期中考试要求,如果你们感兴趣的话可以去读一下

耶鲁公开课 - 金融市场课程节选

You take notes any way you choose, but if you don't get anything on there it'll be available online.

你可以用自己的方式做笔记,但如果你不想记笔记,也大可直接下载课件

耶鲁公开课 - 心理学导论课程节选

But you can also look at it qualitatively, so, if you think about the force between the electron and the proton, you could just qualitatively think about what's happening.

但你也可以定性的来研究这个问题，所以如果你们考虑电子,和质子之间的作用力,你可以定性的来想。

麻省理工公开课 - 化学原理课程节选