I don't know how many kids, generation after generation, get in trouble because they do not remember the following fact.

我不知道有多少孩子,一代又一代,因为没有记住下面的内容而遇到困难

耶鲁公开课 - 基础物理课程节选

And secondly, I think that, even if they don't know how to do a problem,

二是，我觉得，即使他们不知道怎么做一道题，

体罚是不可取的 - SpeakingMax英语口语达人

But if you say, well, I don't know how to do this, I am not going to bother, don't grade the paper.

但是如果你说，好吧，我不知道怎么做这个，我想麻烦，别给试卷评分。

麻省理工公开课 - 固态化学导论课程节选

He had a little electrical thing just on— I don't know how he thought to do this.

将一个小型的电极插在,不知道他是怎么想到要这么做的

耶鲁公开课 - 心理学导论课程节选

I don't know how to turn it on, I don't know what to do.

我不知道怎样打开，不知道要做什么。

麻省理工公开课 - 媒体、教育、市场课程节选

I don't know how to do it really.

我不知道要多快才行。

麻省理工公开课 - 热力学与动力学课程节选

What I was going to say is that you could, at least theoretically, strike with your spear in a overhand manner or you could strike with it in an underhand manner, the only thing is I don't know how you do that underhand when you're in the middle of a phalanx.

我要说的是,士兵们能够,至少从理论上来说,可以自上而下地刺矛,也可以这样自下而上地刺矛,我不太清楚在方阵中,士兵们怎么能够自下而上地刺矛

耶鲁公开课 - 古希腊历史简介课程节选

But notice what this does. The first thing it does is, it says, let's check and make sure x is greater than or equal to 0. If it isn't, notice what's going to happen. None of that block is going to get executed, and it's going to come down here and print out a useful piece of information, which says, hey, you gave me a negative number. I don't know how to do this.

做的是和以前一样的事情,但是注释它做了什么，第一件做的事情就是,程序说，要去检查并且确信x是大于等于0的，如果不是的话，请注意会发生什么,下面的代码都不会被执行,程序会到这里来然后显示一些有用的信息,信息会说，嘿，你给了我一个负数,我不知道该怎么弄这个了。

麻省理工公开课 - 计算机科学及编程导论课程节选

I don't know how to do that.

因为没有办法这么做。

麻省理工公开课 - 热力学与动力学课程节选