题目

（本小题满分12分）如图，AB、BC、CD分别与⊙O切于E、F、G，且AB∥CD．连接OB、OC，延长CO交⊙O于点M，过点M作MN ∥OB交CD于N．【小题1】⑴求证：MN是⊙O的切线；【小题2】⑵当0B=6cm，OC=8cm时，求⊙O的半径及图中阴影部分的面积． 答案：【小题1】解：（1）如图，∵ AB、BC是⊙O的切线∴ OB平分∠ABC，即…………（2分）∵ BC、CD是⊙O的切线∴ CO平分∠BCD，即…………（4分）∵ AB∥CD    ∴∠ABC + ∠BCD = 180°∴∠OBC + ∠OCB = 90°…………（5分）∴ OB⊥CM∵ MN∥OB     ∴ MN⊥CM∴ MN是⊙O的切线…………（6分）【小题2】（2）连结OF    ∴ One Friday Mrs. King asked her class to write a story after class. “Use your imagination!” she cried, “You can write your story about anything.” Kenny looked worried. “A story?” he thought, “What could I possible have to write about? I don’t know any stories.” The bell rang and all the kids went home. The next day, Kenny sat at his desk at home, thinking and thinking. The warm sun was shining through the windows, making him drowsy. And soon he fell fast asleep. As he slept, Kenny began to dream about fantastic things.First he dreamed that he was a world-famous doctor, saving whole cities and curing diseases. Then he dreamed that he was in a UFO. He was talking to strange but friendly space creatures. Then he dreamed that he had become as small as a mouse by a bad scientist. He had to find a way to stop the plot（阴谋）of the mad scientist!Kenny dreamed wonderful and exciting things until his little brother woke him up. “What were you dreaming about?” he asked. Kenny told his brother the wonderful dreams. His brother enjoyed the stories. Suddenly, Kenny knew that he had his kinds of stories in his imagination.小题1:What did the teacher ask the students to do as homework?A．To act as a doctorB．To read some storiesC．To help family membersD．To write a story小题2: How many dreams did Kenny have?A．OneB．TwoC．ThreeD．Four小题3:What was Kenny in his first dream?A．A great doctorB．A mad scientistC．A visitor on a spaceshipD．A good student小题4: The underlined word “drowsy” means_______.A．unhappyB．sleepyC．upsetD．awake小题5:The best title for this passage is _______.A．A strange dreamB．Mrs. King's classC．Writing a story with imaginationD．An evil scientist