1.crack a smile 微笑；莞尔一笑

例I was telling my jokes to her, but Susan never cracked a smile.

2.smile from ear to ear 高兴大笑得合不拢嘴

例 She was smiling from ear to ear as she accepted the prize.

3.be all smiles 笑容满面

例 She spent the whole of yesterday shouting at people and yet this morning she’s all smiles.

她昨天一天都在和别人大吵大叫的，今早却笑容满面。