I'm exhausted. I tried several methods. I thought of this method at the beginning, but finally forgot to extend DM and EE 1. What a failure! No wonder, I haven't done solid geometry for a long time, and I'm a little rusty. To tell the truth, I finally set up a coordinate system to find the intersection equation and then find a special point on it before pushing it in turn. If you are interested, I can give you the process. I'm so tired, please give me a good evaluation!