but sometimes you think you forget

但有时你以为自己忘了
and it's because you haven't looked long enough.

其实是因为你并没有努力地去回忆
There's a real physical notion of searching for the right answer.

寻找正确答案是有生理概念的
We've talked about retrieval.

我们已经讨论过提取
Oh. Every class I've given

每次我上课
somebody asks either in class or by e-mail

都会有人在课堂上或通过邮件问我
what about deja vu?

记忆幻觉是怎么回事
And deja vu is a feeling

记忆幻觉是一种感觉
that an event has happened before.

你感到事情曾经发生过
So, you're looking at me and I'm lecturing and you say,

比如你听我讲课然后你说
"I've heard this before.

"我以前听过这个
I know this before.

我以前就知道这个