Mr. Clarke works in a middle school. He likes reading and often 1some books from the library. He listens to the radio every morning and reads2after supper. So he knows much and teaches well. His students worship ( 崇拜) him very much. Mike, Mr. Clarke's little son, is only nine. He 3likes reading books. And   he often asks his father some questions. Mr. Clarke always thinks he's too young to underst and him and chooses 4ones to answer. Of course the boy is not satisfied with （对……满意）it. One day Mike read 5about the electric lights (电灯) and was 6it. When his father told him to do some housework, he went on thinking of it. He asked him a few questions, and his father answered all. Then his father said, "Fathers always know 7than sons!" The boy thought for a while and said, I don't think so." His father asked "Oh? Why?" Mike didn't answer and asked,8, " 9invented the electric lights?" "Thomas Edison." answered Mr. Clarke.  "Why didn't his 10invent them, then?" Looking at his son, Mr. Clarke didn't know what to answer!