你知道南京吗？这个假期我去了南京。如果你不知道的话，我将会介绍这座美丽的城市。

Do you know Nanjing? I went to Nanjing on the holidays. If you don't know it, I'll tell you something about the beautiful city.

youdao

如果你不知道的话，问问俄罗斯人吧- - -他们知道一些能够安然度过危机的好方法。

If not, ask the Russians - they know some nice ways of how to survive the crisis...

youdao

如果你不知道的话，那么就去找一个曾经经成功搭建梯子获得自己的馅饼的人，问问他该做些什么准备工作。

If you don't know, find a person who has managed to build a set of stairs to reach his pie, and find out what needs to be done.

youdao

If you don't have the units, then if you say the answer is 19, then we don't know what it means.

如果没有的话,比如你的答案是十九,那我们就不知道这是什么意思

耶鲁公开课 - 基础物理课程节选

bug And maybe by understanding why it worked on a and not on b, you'll get a lot of insight that you won't if you just focus on the bug.

发现很多东西，而你只关注,本身的话就发现不了这么多东西,如果知道你的程序至少还对。

麻省理工公开课 - 计算机科学及编程导论课程节选