Reliable. Everything on Douyin is certified and will be inspected. If it is not authorized or irregular, it cannot be put on the shelves. The courses you can buy on Douyin to upgrade to a bachelor's degree and improve your scores are reliable. The junior college-to-undergraduate examination refers to the selection examination for college-level students to enter undergraduate-level studies. It is the examination system for college-level students to enter undergraduate institutions in the education system of mainland China.