我不知道什么是爱情？

I don't know what is Love?

youdao

我不知道什么是绝对的真理。

I am ignorant of absolute truth.

youdao

我不知道什么都看不见是什么样的感觉。

I don't know how it feels to be blind.

youdao

I certainly didn't understand how they even connected really to chemical reactions, much less other disciplines that I was interested in.

它们这么重要,我并不理解这些分子是什么，我也不知道它们。

麻省理工公开课 - 化学原理课程节选

I chose English Literature because when I started off a university, I didn't know what it was I wanted to do.

我选英语文学是因为当我刚上大学的时候，我不知道自己到底想做什么。

为何选那门专业？ - SpeakingMax英语口语达人

I don't actually know whether it's deserved or not, because Yale does not publish information about what the grading averages are.

我不知道这名声是不是我应得的，因为耶鲁并没有对什么是普通的评分标准,发表文章。

耶鲁公开课 - 死亡课程节选