Generally speaking, the question is not difficult, but it is novel and difficult to answer. Choosing normal, 1 1. 12 is a little difficult. Fill in the blanks simply. Big question (2) The first question is difficult. 18 is very simple. 19 is novel but quite simple. 20.2 1 is normal and difficult. They all said that 23 was difficult to choose, so I made 24 easily.