So if you wanna do something conditionally, you generally needs to ask the question, is the following true or false.

假如想在一定条件下做一件事情，你需要判断下这个条件，来看看条件是真还是假。

哈佛公开课 - 计算机科学课程节选

And what he said was that when you get down to atomic length scales there are limits, there are constraints on our ability to observe.

讲的就是,当你去进入到原子长度的尺度中,我们的观察能力,有一定的限制条件。

麻省理工公开课 - 固态化学导论课程节选

Because you're going to run it and you'll probably find conditions under which you can run it more or less to completion.

因为如果你想进行这个反应,你总可以找到一定的条件,来或多或少实现这个反应。

麻省理工公开课 - 热力学与动力学课程节选

Once you get a formula, you've got to always remember the terms under which the formula was derived.

使用公式时,你一定不能忘记,公式使用的前提条件

耶鲁公开课 - 基础物理课程节选

So, marginal land is brought into play with hard work and ingenuity, and this is one of the things that Hanson emphasizes that is so helpful.

那么,边际耕地需要,在一定的生产条件下,生产收益正好足以补偿所需费用的土地,这就是汉森所强调的相当有益的一点

耶鲁公开课 - 古希腊历史简介课程节选

The biodiversity has shrunk for various reasons of profitability and as a consequence of that things like corn crops, and the orange crops in Florida are particularly susceptible to certain environmental conditions, certain pests, and certain types of blight.

生物多样性的减少源自利益的驱动,和玉米一样,佛罗里达的柑橘作物很容易受到,一定环境条件的影响,还有虫害和枯萎病

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

That tells you something about the physical chemistry of the molecule; that it's these hydrogen bonds that hold the double strands and I can break those down under certain conditions.

我们从中可以知道一些,DNA分子的理化特点,双链是由氢键连接在一起,在一定条件下这些氢键可以断裂

耶鲁公开课 - 生物医学工程探索课程节选

The native structure is this double stranded structure here and if I heat it up slightly and I add some base, so under slightly basic conditions, these molecules will fall apart because you've created conditions where the hydrogen bonding is no longer favorable so they peel apart.

原始结构,在这里就是指DNA双链,如果我稍微加热,并且加入一些碱,在弱碱性的条件下,这些配对碱基会分开,这是因为在一定条件下,碱基对之间的氢键,不再稳定并且会断裂分开

耶鲁公开课 - 生物医学工程探索课程节选