But as she watches her students run through the woods,she smiles, and says it's a good start.

VOA: standard.2010.06.25

It turns out that these different smiles have real psychological validity.

这说明这些不同的微笑,有真正的心理学效用。

耶鲁公开课 - 心理学导论课程节选

And the best part I would have to say about it is the smiles I put on everybody's faces.

让我说，最好的一点就是我能让人人都微笑，开心。

我就是超人 - SpeakingMax英语口语达人

You could--It's not difficult to study smiles in the real world.

在现实世界研究微笑不难。

耶鲁公开课 - 心理学导论课程节选