I'll never forget what you have done for me.
我将永远不会忘记你为我做的一切。
I'll never forget the happy days we spent together.
我将永远不会忘记我们一起度过的快乐时光。
I'll never forget my first teacher who taught me to be an honest man.
我将永远不会我的第一位老师，是她教我要做一个诚实的人。