If the question of time is not explicitly brought up, then you should know that you have to use this formula.

如果时间的问题并没有明确提出,那你应该知道,必须要用这个式子

耶鲁公开课 - 基础物理课程节选

Yeah, but I think it's also an important skill. You need to be able to express what you know

难，但是我也觉得这是一种重要的技能。你必须能够把你知道的表达出来，

沟通很重要 - SpeakingMax英语口语达人

It would be much better if you had a reference point that didn't care where the pressure was.

我们还需要精确地定义气压,你必须知道气压的大小,当然如果我们能找到一个。

麻省理工公开课 - 热力学与动力学课程节选

You have to know where the vowels are supposed to go, and that makes it harder to learn how to read, but when you have the vowel sounds it's easier and the Greeks made that contribution.

你必须知道这些元音都应该加在哪,这使的学习阅读变得更加困难,但是如果填入元音,那么就会简单点,而希腊人在这方面做出了贡献

耶鲁公开课 - 古希腊历史简介课程节选

hi3 Whereas Hi3, I just created, it happens to live in this directory but my computer doesn't know that so you do dot slash which says current directory.

至于我刚刚创建的,它正好位于我电脑不知道的位置,所以你必须敲入，/，这代表当前目录。

哈佛公开课 - 计算机科学课程节选

But Newton's law is-- You see, you've got to go back and wipe out everything you know.

但牛顿定律是,如你所知的,你必须回到过去,忘掉你所知道的一切

耶鲁公开课 - 基础物理课程节选

because you need to know like, how fast the shutter speed and all that stuff,

因为你必须知道，像快门的速度，还有其他这一类东西，

体育相片的魅力 - SpeakingMax英语口语达人

but definitely have your goals, you know, lined up, and, and you will be okay.

但是必须有自己的目标，你知道，列出来，然后你就一切都好了。

为我的生活 - SpeakingMax英语口语达人

In order to attend, you must know the date and the time. You can ask your friend, "When is your wedding?"

为了能够出席，你必须知道具体的日期和时间，你可以问你的朋友，“When is your wedding？”

When 课堂 - SpeakingMax英语口语达人

That means, when I take two derivatives, I want to get a, then you should know enough calculus to know it has to be something like at^, and half comes from taking two derivatives.

也就是说,当我想求二阶导时,得到了a,你应该有足够的微积分知识,才能知道必须有类似at^的项,而这个1/2则是因为求了两次导数

耶鲁公开课 - 基础物理课程节选