It is the key to obtain this guarantee to choose a high-quality simulation question that meets the review in the middle and late stage. This simulation topic should not be too many, but it must be of high quality. Taking all factors into consideration, the author thinks that "8 sets of 2009 postgraduate mathematics simulation papers" written by Wan Xuehai, Jolin Tsai, Hu Jinde and Cheng Qiyuan, the former proposition marking experts of the Ministry of Education, is the most suitable for candidates. Other simulation questions, some of which are too numerous and some of which are not of high quality, have the biggest disadvantage that the selected questions have been cited many times by some guidance books and classes, which makes candidates feel no novelty when using them to do simulation exercises before the exam, and cannot really reflect their review level. Wang Shian, Jolin Tsai, Hu Jinde and Cheng Qiyuan wrote this simulation question, the quality and height are equivalent to the real question, but it is not completely equivalent to the real question in previous years. This makes candidates have a brand-new feeling when doing the simulation questions of this book, which can help candidates really find the shortcomings and defects in the review process, test their true level and help candidates succeed in the 2009 postgraduate entrance examination. Therefore, the author thinks: At present, the "8 sets of postgraduate mathematics simulation papers in 2009" compiled by four professors, Wang Shian, Jolin Tsai, Hu Jinde and Cheng Qiyuan, is the best.