Problem solving is inefficient because you are not skilled. For example, we did too much at that time, and then except for the last big question, we basically saw the understanding method at a glance, so it is very important to do more questions, but at the same time, you should also learn to use them flexibly. For example, the multiple-choice exclusion method is very easy to use, although I never use this method in mathematics, and you should be good at using substitution method, such as substituting some simple numbers or figures to meet this problem. This is the skill of multiple-choice questions and fill-in-the-blank questions, and if you really don't know how to do multiple-choice questions, substitute each option into the meaning of the questions, but pay attention to the time. At that time, I basically finished all the previous questions in 20 to 30 minutes by using these skills, and I got full marks every time, and I made one or two mistakes at most, so skills are very important, and this also requires you to learn from the questions you have done, and you can make mistakes by taking the wrong book. In addition, if your foundation is not particularly good and the university you want to enter is just ordinary, you can give up some difficult problems selectively, and it is basically no problem to get the scores of simple questions, but you must be cautious.