Dear friend,
       I am an American (美国的 ) girl. My name is Alice Green. I am a middle school student. I am fifteen. I have two brothers. They are middle school students, too. We go to school from Monday to Friday. We don't have any classes on Saturdays and Sundays. My father and mother are teachers. They always say China is great. I like reading. I am reading a Chinese book. I think it's very interesting. My brothers and I like playing football and basketball. What sports do you like?
     Let's be good pen pals (笔友), OK? Please write to me soon.
Yours,
Alice Green

如图，△ABC内接于⊙O，∠A=40°，则∠BOC的度数为（  ）

小明用如图所示的实验装置，探究反射光线与入射光线是否在同一平
面内，应进行的操作是（　　）