First, systematize the basic knowledge.

When we see a question, we need to know what it is testing, and we need to know clearly which part of knowledge each knowledge point comes from. Keeping in mind the key points, difficulties and error-prone points of each part of knowledge can greatly reduce our error rate. Just like when you see a fractional equation, you will definitely think of checking the root, when you see a quadratic equation, you will definitely think of calculating delta, and when you see an isosceles triangle, you will definitely pay attention to classification and discussion, and you will definitely think of the integration of three lines.

All the knowledge learned in junior high school has its most basic part and difficult part, which corresponds to the three different requirements of ABC in our senior high school entrance examination requirements. We should know every part of knowledge, especially geometric models, such as single tangent, double tangent and triple tangent between circles and tangents, and non-vertical similarity, double vertical similarity and triple vertical similarity models in similarity, so that we can get the idea of doing the problem faster and more clearly.

Furthermore, for constructing isosceles triangles and right-angled triangles, it is often necessary to discuss who is the waist, who is the bottom, which is the right-angled side and which is the hypotenuse, so the systematic method here becomes particularly important. In order to ensure that the discussion is not lost, it must be divided according to certain principles, otherwise it may be lost and repeated. Therefore, we must learn to summarize the basic questions and basic knowledge points, so as to ensure smooth and rigorous problem solving.