This is the auxiliary material I bought for my son, and it was recommended by my nephew in junior year. It's a teaching aid he used in high school. There are related exercises in all subjects of Examination Questions Survey, covering a wide range. Monthly 1 episode, a total of1episode, which can help master the review rhythm. The test questions are original and innovative, and the selected questions are good. Moreover, it will also introduce the learning methods and skills in detail, so that children can solve all the problems and truly answer the questions correctly. It seems that they have official website. If you want to buy or know about it, you might as well visit them in official website. If necessary, please feel free to ask.