Dear teacher:
I am writing to express my sincere gratitude for your help in my study. Without your hel, my study would not be the top three in my class. It was you who always standed by me when I am fall. You pointed my mistakes and told me how to make them right. You always worked tirelessly to train my patience. Your continuous encouragement is my greatest motivation.
I sincerely hope that you can have a good health and stay happy. In addition, I wonder if you can pay a lot of attention to your health, get more rest.
Again, I sincerely thank you for your help!