我哪知道你在等我？

How was I supposed to know you were waiting for me?

《牛津词典》

“那么他为什么突然感兴趣了呢？”—“我哪知道。”

"So why did he get interested all of a sudden?"— "Search me."

《柯林斯英汉双解大词典》

你哪知道，他总是挑重活儿做。

What do you know; he always volunteers for heavy work.

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

Well, that matters to us, but the trouble is, without predictability you don't know where to put the peak.

那对我们很重要，但问题是，没可预见性你就不知道巅峰放在哪点。

耶鲁公开课 - 死亡课程节选

So something has happened there that wasn't what I expected. Who wants to tell me what that bug is? Yeah?

我已经知道哪一句声明出问题了,一些和我预期不同的事情发生了,有人能告诉我bug在哪儿么？

麻省理工公开课 - 计算机科学及编程导论课程节选