如果不知道，必须尽快弄清楚。

If you don't, you must find out as quickly as possible.

youdao

如果不知道事物的本质，光知道名字有何意义？

What signifies knowing the Names, if you know not the Nature of Things.

youdao

如果不知道正确注射，他们会感染的。

They will get infected without knowing how to inject correctly.

youdao

- "She lived unknown and few could know"-- how can she be unknown if few know anything about her?

她不为人知地活着，鲜有人知道她“,如果有任何人知道关于她的任何事情,又怎么能说他不为人知呢？

耶鲁公开课 - 文学理论导论课程节选

It's very exciting, but if you think you know everything you don't need to learn, you don't belong to us. I always need to learn.

这很令人兴奋，但如果你认为,你什么知道，你不需要学习了，那么请你退出百度，因为人总是在学习。

斯坦福公开课 - 百度CEO李彦宏演讲：全球最大搜索引擎的发展课程节选

If you don't know why you're about to eat cake like that you will soon, but you know this.

如果你现在还不知道为什么将要吃到那样的蛋糕,很快就会知道的，你清楚这一点。

哈佛公开课 - 计算机科学课程节选