微笑 - smile
【释义】
The corners of your mouth move outwards and slightly upwards.
嘴角向外运动并轻微向上扬起。
【例句】
Her smile makes her even more beautiful.
她的微笑使她更美丽了。

大笑 - laugh
【释义】
To make a noise to show one's amusement and happiness. You can laugh at a joke or at an amusing sight. You can laugh at someone without being amused. 
发出声音以表现出愉快的情绪。听到笑话或看到有趣的场景人会大笑。即使没有逗趣的事情人也能大笑。

【例句】
Laugh, and the world laughs with you; weep, and you weep alone.
你笑，世界也会跟着你一起笑。你哭，却只能独自一人。

露齿而笑 - grin
【释义】

To smile with the teeth. 
露出牙齿地微笑。
【例句】
People who confess to feeling happy also grin more than others.
承认感觉幸福的人们也会比别人更喜欢咧着嘴笑。

轻声地笑 - chuckle
【释义】
To laugh quietly. 
不发出声音地静静地笑着。