A flicker of a smile crossed her face.

她脸上闪过一丝微笑。

《牛津词典》

A smile lit up her face.

她微微一笑，脸上露出了喜色。

《牛津词典》

A smile brightened her face.

她的脸上露出了灿烂的笑容。

《牛津词典》

But the look on everyone's face, when you are finished and packing, it is the best smile in the world;

VOA: special.2009.03.22

Then when they stand up and face the crowds, there's a big smile.

但当他们面对人群站立时，他们露出了大大的微笑。

耶鲁公开课 - 心理学导论课程节选

You know, even some goes pass you on the street and you don't smile ostensibly you don't smile-- there are certain micro-muscles in your face that are moving that actually make you feel better.

即使路人与你擦身而过时，你没笑,表面上你没有笑-,但你面部的细微肌肉,会收缩，让你感觉更好。

哈佛公开课 - 幸福课课程节选

The sketch brought a smile to my face, a smile to the face of my two post-Sesame Street-age kids, and, I can only assume, a smile to the face of everyone else watching.

FORBES: SNL, The Muppets, And Sesame Street Know Purpose Is At The Heart Of Great Brands

That little person has put a smile on her face, even when there wasn't much to smile about.

WSJ: The Arnault Legacy

While Obama was talking, Romney more frequently had an openness in his visage, often with a slight smile on his face and very soft eye contact. (Some may view the smile as a smirk, but that is the confirmation bias at play.) I noticed this frequently in the Republican presidential debates.

FORBES: Three Methods of Persuasion You Can Copy From Obama and Romney (and one from Joe Biden that you should not copy)