Personally, it is relatively simple to compare the top 20 questions (150) on a single basis. As long as the foundation is solid, it is estimated that the on-site response of 130 should be better, and candidates with a bad sense of space of 17 should tear a square directly according to the picture. 18 can be understood at once, as long as you can bear it slowly. It is said that 19 is difficult. The first question should be asked. The second question is really bad. You can ask for writing and estimation according to known conditions. 20 questions are usually estimated to be practiced frequently, so the whole is not difficult.