要生活，你首先必须存在。

To live, you have to exist at first.

youdao

“很好，”士兵说，“那么，首先你要帮我从这口井里出来。”

"Good," said the soldier, "then in the first place help me out of this well."

youdao

首先，最重要的是要考虑你的观众；在此情况下，你的观众是你组里的其他学生。

First of all, the most important thing to consider is your audience, and in this instance, your audience are the other students in your group.

youdao

And the first thing you do is ask is it an instance of some problem that other people have already solved?

而且你以前从没碰过这个问题,你首先要做的一件事就是问问自己,这是不是一个别人已经解决了的问题？

麻省理工公开课 - 计算机科学及编程导论课程节选

So, if we want to think about what the first ionization energy is of boron, what you want to do is write out the electron configuration, because then you can think about where it is that the electron's coming out of.

如果我们要考虑,硼的第一电离能，你首先要做的是写出它的电子排布，因为在这之后,你才能知道拿走的是哪里的电子。

麻省理工公开课 - 化学原理课程节选

So, essentially you've got a positive ball which is identical to the size of the atom.

首先你要有一个和原子差不多大小的,带正电荷的球。

麻省理工公开课 - 固态化学导论课程节选