Sara Smile features only three newly-composed songs.

VOA: standard.2009.12.30

Now if you smiled to-- or make three people smile, and these three people-- each one makes three other people smile.

如果你的笑-,感染了三个人，这三个人-,每个人又引起另外三人发笑。

哈佛公开课 - 幸福课课程节选

Within 20 degrees of separation from you initial smile to the three people, the entire world will be smiling.

只需要20度的分隔,从你用笑容感染三个人开始，全世界就会笑起来。

哈佛公开课 - 幸福课课程节选

Now, the person who is the mandated smiler, on three, please smile. One, two, three. Okay.

现在，要求微笑的一方，我数到三，微笑，一，二，三。

耶鲁公开课 - 心理学导论课程节选

And those nine people make three-- each one-- three other people smile.

那九个人-,每个人再用笑容感染三个人。

哈佛公开课 - 幸福课课程节选