No one seems to know for sure.

VOA: special.2010.06.27

It's been disputed and one doesn't know for sure.

尽管这点还存在争议。

耶鲁公开课 - 文学理论导论课程节选

it's Shopbot for people, you know, make sure things sell,

对人们来说，那就是个比价器，确保东西卖得出去，

在布鲁明戴尔百货 - SpeakingMax英语口语达人

As I'm sure you know, Socrates was put on trial, condemned to death for corrupting the youth of Athens-- and perhaps, among other things, for arguing philosophy with them.

想必你们都知道,苏格拉底被人指控,以教唆雅典青年的罪名,被判处死刑,也许,罪名还包括,和青年们讨论哲学

耶鲁公开课 - 死亡课程节选

Let's assume you know that for sure.

假设你对此确信无疑。

耶鲁公开课 - 公正课程节选