题目

阅读理解 The executive committee of the WorldAnti-Doping Agency(WADA，世界反兴奋剂组织) agreed to aseries of tough measures against Russia on December 9. According to TheWashington Post, it is the most severe punishment to date in the years-longRussian doping saga (兴奋剂事件). Russia is prohibited from participatingin all major international sports events in the next four years, including the2020 Tokyo Olympics, the 2022 Beijing Winter Olympics, and the 2022 FIFA WorldCup in Qatar. The country will also be banned from hosting any major sportsevents. The reason for such sever已知：∠AOB和两点C、D，求作一点P，使PC=PD，且点P到∠AOB的两边的距离相等．（要求：用尺规作图，保留作图痕迹，不写作法，不要求证明）