如果这第一层油漆看上去有点脏的话，不用担心。

Don't worry if this first coat of paint looks messy.

《柯林斯英汉双解大词典》

如果这是你的第一胎，你就非常有可能会太早到医院。

If this is your first baby, it's far more likely that you'll get to the hospital too early.

《柯林斯英汉双解大词典》

如果你失业了，第一感觉通常是震惊。

If you've lost a job, the first feeling is often one of shock.

youdao

So, here's the reading. So, for example today, there is a vision statement, administrative details and I'm going to get a little bit of teaching towards the end. And, if you wanted to, you could crack the book and look at chapter one.

这是阅读材料，例如说，今天，有一个远景说明，行政管理的细节,末尾的时候我会讲一些教学的内容,如果你们想要的话，你可以打开那本书，翻到第一章。

麻省理工公开课 - 固态化学导论课程节选

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

If you take some from column one or two and you mix it with some from column eight and nine, bingo, you have reaction.

如果你从第一列或者第二列中选出一些元素,将其与第8列或者第9列的元素混合，好，就会发生化学反应。

麻省理工公开课 - 固态化学导论课程节选