Dear teacher:

Hello. We haven't seen each other for a long time. But I still remember the days we went together. You are really a good teacher who not only passes us knowledge but also treat us like your own children. I remember that all the classmates liked to play with you at that time. I spent a very happy time with you. Now, I am studying in an university, my major is international trade which requires a high level of English, since you gave me a stable base, I find it easier to learn my major. When I graduate, I may study abroad and when I return China, I will try my best to contribute to society.

Yours,

XXX