One word then, one smile, is enough.

彼时，一个字，一个微笑，就已足够。

youdao

Just one smile from you would make my whole world bright.

你的一个微笑，将照亮我的整个世界。

youdao

If you have only one smile in you give it to the people you love.

如果你所拥有的只是一个微笑，那就送给你爱的人。

youdao

Then comes hope with a sweet smile and says softly, 'There is joy in forgetting one's self.'

VOA: special.2009.11.15

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

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

Mr. GREEN: (Singing) One smile that cheers you.

NPR: Songwriter Betty Comden

And no one seemed to smile or make small talk as jurors filed out of the courtroom for breaks.

CNN: June 17, 2012 -- Updated 2034 GMT (0434 HKT)

Is that smile one of friendship or triumph?

FORBES: People I'm Grateful for #5: Paul Ekman