His face cracked into a smile.

他脸上绽出了微笑。

《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》

A smile suddenly animated her face.

她嫣然一笑，立显容光焕发。

《牛津词典》

Her eyes showed traces of tears, but her lips were bravely curved in a smile.

VOA: special.2010.05.15

Talk of smiles is just a way of talking about the ability of the body to smile, to form a smile.

我们会谈到笑只是为了表达,肉体具有笑的能力,能够微笑

耶鲁公开课 - 死亡课程节选

And he's not really very happy as opposed to a smile like this, which is a real smile.

他并不是很高兴,相反的是这样的微笑，这是真正的微笑。

耶鲁公开课 - 心理学导论课程节选

At first, they are told to press the space bar whenever they see a smile.

NEWYORKER: Don��t!

"Yeah, I've got the gray hair, but I feel fantastic, " he said with a smile.

WSJ: Goal for Jets' Ryan remains same despite changes

'If you fall in, you'll probably get spit out eventually, ' he says with a smile.

BBC: The perfect trip: The Canadian Rockies