grin

The toddler began to grin when he saw his father hiding behind the curtain.

(Chinese) 看到爸爸躲在窗帘后面，那个蹒跚学步的孩子开始咧嘴笑了起来。

Stop grinning like that and tell me what the big surprise is!

(Chinese) 别那样咧嘴笑了，快告诉我那个大惊喜是什么！

She had a wide grin on her face when she won the first prize in the art contest.

(Chinese) 当她在艺术比赛中获得一等奖时，脸上露出了灿烂的笑容。

The mischievous boy had a huge grin as he showed us the frog he caught.

(Chinese) 那个淘气的男孩在向我们展示他抓到的青蛙时，露出了大大的笑容。