你突然知道什么是重要的事了？

All of a sudden you know what's important?

youdao

好吧，我们突然知道我们可能是找到一颗行星，上面可能有充满了复杂的，有智慧的生命。

Well all of a sudden we know we could have a planet teeming with complex and intelligent life.

youdao

“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》

And what happens of course thereafter, as you'll remember, is that Lily pops up from the back seat: "Hi." He didn't know that she was there.

那么，在那之后发生了什么呢，正如你所记得的,莉莉从汽车后座突然跳出来，你好，他根本就不知道她在那儿。

耶鲁公开课 - 1945年后的美国小说课程节选

I have songs that just come to my head, you know,

我脑中会突然出现一些歌，你知道

唱片即将上市 - SpeakingMax英语口语达人

You might ask though,is there some other behavior, something else that should tip us off,could tip us off, as to whether or not we really do or don't believe that we're going to die?

你可能会问，有没有其他行为，能够让我们突然醒悟，知道我们真正是否相信自己会死呢？

耶鲁公开课 - 死亡课程节选