参考范文：
Dear sir，
I am writing to you to express my thanks for your help in learning English。 You are one of the best teachers who I have ever met 。There are many good points that I learn from you。
During these days in your class， I have acquired much knowledge from you and it really helps me a lot。 Firstly， you let me know what the west thinking pattern is -straight thinking pattern。 As an English learner， it is important for me to understand the difference between them。 There is no denying the fact that this can help me with my examination and interaction with foreigners。 What’s more， I’m glad to be your student， and I am very happy to learn the course under your guidance。 English is an important tool， through which we can share our experience with the world。 I treasure the chance of learning English， and I enjoy the happiness from your course。
The last not the least， please forgive those mistakes I have made which may upset you。 What I have learned from you will help me pass the coming examinations and also be useful for my further education in abroad。 It is not only a progress of learning， but also a cultivation of my ability。
May everything go well around you。
Your student，
Li ling
