Dear Xiao Dong,
I’m sorry you are having trouble in learning English in senior high school. However, the situation is easy to change if you take my advice. Here are some tips to help you.
Firstly, why not try to communicate with others in English? If you do so, you will feel confident gradually. Also, don’t be afraid of making mistakes because everyone makes mistakes. Secondly, you should keep on reading aloud English sentences every every morning and evening. That way, you’ll learn many important expressions. Thirdly, it would be a good idea if you read more English newspapers and watch English movies.
I hope you will find these ideas useful.