It's just clear mind, clear thinking.

就是清醒的心智，清醒的思考。

攀岩的刺激 - SpeakingMax英语口语达人

You can see that as you fill up your periodic table, it's very clear. But also we'll tell you a pneumonic device to keep that in mind, so you always remember and get the orbital energy straight.

在你们填周期表的时候，非常清楚但是我们也要告诉你们,一个策略去记住它，所以你们总是记得,并得到连续的轨道能量。

麻省理工公开课 - 化学原理课程节选

It may not be clear to you on a tenth reading, unless you approach it with the proper questions and the proper frame of mind.

可能在第十次阅读时仍是如此，除非你在着手阅读时,持有适当的问题,及合宜的心情。

耶鲁公开课 - 政治哲学导论课程节选

It really helps me clear my mind,

这能让我的思路清晰起来。

Why don't 实战 - SpeakingMax英语口语达人

Maybe when people make the claim, it's not clear which of these things they've got in mind.

也许人们提出这个说法时，他们自己脑中也不清楚是哪一种。

耶鲁公开课 - 死亡课程节选