If you are in Beijing, go to Tsinghua to find "Shan Shan Academy" or "Teaching Material Center", tell the book seller which department and grade you are in, and he will tell you what books to buy (if it is a department with few people), and then get it done. Or before the start of school, these bookstores will prepare a list of textbooks needed by various departments and grades, and you can buy them at will.