You must think, in order to prove this problem, you must ... these conditions and see what is known. With these conditions, oh, this condition is still needed. Then find conditions to prove that this condition is poor,

Then all the collocation is completed and the problem is proved.

Remember, you have to put off the question.

Show the known conditions with a pen on the chart for easy analysis.

And you have to remember some theorems, some special angles, special shapes and so on.

When some problems cannot be proved,

You should pay attention that you may need to add auxiliary lines, such as what I said just now.

You can draw a line segment or parallel line to supplement the conditions, which is clear at a glance, but some auxiliary lines that are difficult to see depend on your actual combat experience, so you have to do them seriously.

Keep these firmly in mind, remember the kilometer theorem that the teacher taught you, and you will succeed more than half.