In many classrooms, it's not1to find students spinning (旋转) their pens2they listen to their teachers.
Pen-spinning is also popular3 Japanese students. It is a form of entertainment. Recently, a pen-spinning competition was held in Tokyo, Japan. Ryuki Omura, a 16-year-old high school student, became the first pen-spinning4.
   276 people took part in the competition. The came from different age groups. Some were students5 some were office workers. First, they 6 the videos of their pen-spinning skills to the organizer's website. Then some of them came to the last round in Tokyo. 7 of them had 30 seconds to show their skills in front of 400 people,8reporters and fans. Omura took a pen from his little finger to the rest fingers, then to his palm(手掌) and the back of his hand. His wonderful show made him 9 the champion.
   Omura said he began learning pen-spinning only about 14 months ago. He did 10 in the competition. If you like to spin your pen, you can practice it in your spare time. But when you are in the class, please don’t do that.

如图，直径为AB的⊙O交Rt△BCD的两条直角边BC、CD于点E、F，且 $\widehat{AF}=\widehat{EF}$ ，连接BF．

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