After five years of college entrance examination and three years of simulation, 38 sets in Tian Li are quite good, which are sold in ordinary bookstores. If you are from Jinan, go to Hero Mountain Cultural Market, where books are cheap. It's cheaper than Xinhua Bookstore, but not as complete as Xinhua Bookstore. As long as you do a set of questions that suit you, you don't need to buy a lot, otherwise you will be confused in the end.