当你需要运用二者以达到某一既定结果的时候，无论我们如何希望它们能并行不悖地工作，它们都无法如我们所愿。

While you need to employ both to get to a finished result, they cannot work in parallel no matter how much we might like to think so.

youdao

现在，如你所知，当你申请我们公司的职位时，我们需要了解一下你的学术背景和最近的工作经历。

Now, as you know, when you apply for a post with our company, we need to find out a few things about both your academic background and recent work experience.

youdao

现在，我们都知道，当你真需要电池时它们总没电。

Now, we all know when you really need batteries, they're dead.

youdao

And, that's a good thing to know because if you come out with an answer that's somewhere near the diameter of the universe and it's supposed to be the diameter of an atom, then you will know that you probably made a mistake.

这是我们需要知道的,因为当你做一道题得到的答案,是宇宙的直径,而正确答案是原子直径时，你能很快发现你的错误。

麻省理工公开课 - 固态化学导论课程节选

And that we need to see your work to get full credit, and then especially if you get things wrong, we need to know where it went wrong.

我们需要看到这些才能给你所有分数，尤其是当你出错的时候，我们需要知道是哪里错了。

麻省理工公开课 - 化学原理课程节选