You can write hope that teachers can be healthy and happy forever, work smoothly, and so on. As long as it is a blessing, the teacher will be very happy.

Teacher: Teacher X, I am your student xxx. In your years of teaching career, I may not be the best. However, I believe that you are the most important mentor and friend when I was growing up. Thank you sincerely, my teacher. I hope you can always be happy, healthy, smooth in your work and happy in your family!

Classmate: xx, your best friend, sincerely wishes you happiness every day, academic success and ideal realization. May our friendship last forever!