congratulate sb.on/upon sth.
为某事向某人祝贺
下面转帖-
1,congratulate 是一个动词.
To express joy or acknowledgment,as for the achievement or good fortune of (another).
因为某种成就或者财富,表达喜悦或者认同.
例子：She congratulated him on passing his driving test.
2,congratulations to sb 可以理解为惯用语.
例子：Congratulations to you!恭喜你
Congratulations to him on winning the Academy Award.祝贺他获得奥斯卡奖