If you are not a genius, it is basically impossible if you are not exposed to a lot of high school content in junior high school. I learned a lot of chemistry in junior high school because of the chemistry competition. It took me two weeks to preview all the contents (one semester, three hours a day), and the correct rate of doing the questions was 70%-90%. It took such a long time to learn only one subject and foundation, and the science in Grade One became materialized. It would be even more troublesome if mathematics was added, because mathematics was studied twice a semester, and four books were materialized in Grade One. Plus there are 10 books on mathematics, which is not difficult. If you are confident enough, you can try, but you will be very tired and don't know what it means to be fully mastered. Even after studying for three years, few people can get full marks in the science exam of senior one. How can you call it complete mastery?