我不知道该走哪条路，我听到有人在哭。

I didn't know which way to go and I heard someone crying.

youdao

我不知道为什么所有人都为几只蚊子发这么大的牢骚。

I don't know why everybody makes such a fuss about a few mosquitoes.

《柯林斯英汉双解大词典》

你们当中可能有人不知道，草原犬鼠其实不是狗。

For those of you who don't know, prairie dogs are not actually dogs.

youdao

And we graduated the same year -- now no one has to say what year that was, even if you know, but we did graduate the same year.

我们同一年毕业的-,当然我不要求你们说出是哪一年，可能有人知道，我们在同一年毕业。

麻省理工公开课 - 化学原理课程节选

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

I mean, I don't know, I don't know the criticism... Yeah, I think they would say that.

别介意，我也不知道到底会面临什么样的批评。。。,是的，我觉得会有人这么说。

普林斯顿公开课 - 人性课程节选