情景设定：假如你叫韩梅，是一名交换生，初到美国林肯大学（Lincoln University）学习，现在给你的朋友陈燕写

One possible version:

Dear Chen Yan，

Thanks for your letter. I’m an exchange student. I am busy but happy now. I am studying at Lincoln University. At the beginning, I couldn’t understand the teacher in class. Her English is quite different from what we heard in class in China. But I am lucky enough because my classmates are really friendly and kind and the teachers are helpful. After class, I talked with them in English as much as possible. When I had any questions, I asked the teachers for help. Now my English has improved a lot and I have less difficulty in class than before.

Best wishes！