在一个不透明的袋子中装有红、黄两种颜色的球共20个，每个球除颜色外完全相同．某学习兴趣小组做摸球实验，将球搅匀后从中随机摸出1个球，记下颜色后再放回袋中，不断重复．下表是活动进行中的部分统计数据．

（1）完成上表；

（2）“摸到红球”的概率的估计值是____（精确到0.1）

如图，折叠直角三角形纸片的直角，使点C落在斜边AB上的点E处，已知AB=8$\sqrt{3}$，∠B=30°，则DE的长为(      )

二十四节气是中国农耕文明的宝贵遗产。即使中国古代有着自己的授时系统，但古代的人民群众在一定程度上仍依靠二十四节气指导生产和生活。不可否认的是，少数地方的节气传统正在消减，年轻人对节气的认知逐渐淡薄，由于近年来城市化进程过快，这直接弱化了二十四节气的各种功能。二十四节气申遗成功后，我们只要加大宣传力度就能做好传承和保护工作。

①假设关系不成立，应当修改为：虽然中国古代有着自己的授时系统。

②____，应当修改为：这进一步弱化了二十四节气的各种功能。

③条件关系不成立，应当修改为：____。

     Mr. Baker was a strong man. He liked playing football and spent a lot of time on the game when he studied in a medical college. But his right leg was broken when he was playing football with his friends. He couldn't play football any longer. He was sorry for it and still liked to watch the game.

      Now Mr. Baker works in a hospital. He is a good dentist and many patients ask him for help. He is always busy and has little time to watch the matches. He has to watch them on TV at home in the evening. But the biggest football match in their city would start at four one afternoon. Mr. Baker hoped to watch it, but the head of the hospital didn't agree. "You can't go out until all the patients in your office leave. " he said.

     It was three twenty when there were about ten patients in the waiting-room. Mr. Baker was worried. He thought for a moment and had an idea. He said to a woman who was lying on the dental chair,"Cry loudly,Madam! I'll pull your bad tooth out for free if you frighten away the other patients!"

根据短文内容，判断句子正误。