Dear Wenqi,
I received your letter this morning. I learned that you have two problems in English. Now I will give you some advice on how to learn English.
First, you'd better learn the new lesson in advance, such as the new words ' pronunciation and meaning, the article's meaning. In English class you should listen carefully and take notes.
Second, you should speak English with your classmates very often, it's the best way to improve your English level.
I think you should have a try.
Best wishes and good luck!
Yours,
Linda