Thanks for your reply.
Sorry for my lack of English，there may be some grammatical mistakes or a verbal offense.It was never my intention.
First of all，expense is not a problem of my family.
Second，as what you said，base on the difference between two cultures，we do think grade is everything ，therefore we spend all the time to achieve higher and higher score，it makes me a little ashamed.My only two hobbies are writing novels and digging into topics of mathematics.Except for uploading some videos for explaining mathematical Olympiad problems on platform and publishing original novels，I do not have that kind of special experiences，let alone the achievements.I wonder if these can help with my application.
In fact, I love sports, but I don’t have a specific sports specialty.
It seems to be due to cultural differences. Volunteers are very rare in our society. As a student in a bilingual school, I have learned about the idea of using volunteer activities to apply, but I have not found such opportunities. So if I want to get into a good boarding school, do I have to spend some time volunteering in the United States？
Finally，I really appreciate for your earnest answer.I‘m considering about your amazing advice.