你真的不知道发生了什么事？

You really don't know what's going down?

《牛津词典》

我们把这个明确一下—你当时真的不知道他在哪儿？

Let's get this straight—you really had no idea where he was?

《牛津词典》

“但是财政形势更加严峻了。”—“啊，我真的不知道。”

"But finance is far more serious."—"Well I don't know really."

《柯林斯英汉双解大词典》

I really have no idea whether it's a fact, and it's not important in My Fair Lady whether it's a fact.

我真的不知道这是不是真的，但是它在窈窕淑女里面真实与否并不重要。

耶鲁公开课 - 文学理论导论课程节选

But it's, you know, no one seems really pissed off or dissatisfied with their lives, you know.

但是你知道，似乎没人真的不高兴或者对自己的生活不满。

加州的天气 - SpeakingMax英语口语达人

And the other thing to point out, which I don't know if this is true or not, but does anyone know -- well that's part's true, does anyone know what the atomic mass of lithium is?

另外需要指出的一点是，关于这点我不知道是不是真的，有人知道--这部分是真的，有人知道锂的原子量吗？

麻省理工公开课 - 化学原理课程节选