This is the same as many students feel. You can get the problem at first sight, which is familiar and simple, but it is not as easy to do as you think. Perhaps it is because of the mathematics reform of the postgraduate entrance examination in 20021that the proposition teacher considers making as many students as possible familiar with and adapt to the reformed topics and questions, so the difficulty is slightly reduced. In addition, it may also be a signal that mathematics will pay more attention to the examination of basic knowledge in the future. Students who take the postgraduate entrance examination should not only pay attention to various methods and skills, but also pay attention to basic knowledge when preparing for mathematics. After the exam every year, some students will find it difficult, while others will find it not so difficult.