Long ago ,there lived in Greece a learned man. He was so well known for his good knowledge of almost everything that lots of people from all over the country came to learn from him. The great man taught his students whole-heartedly and answered their questions with great patience.
One day a student asked him, “ My dear teacher, didn’t you say you yourself have many ,many more questions about things than we do? But I think we students have far more than you.”
With a smile on his face, the teacher drew two circles ,one as large as a big cake, the other smaller. Then he said , “Of course, I have learned much more. But it’s wrong to think that a teacher has fewer questions than his students. Now, look at these two circles. The inside of the bigger one is my knowledge of things, and the inside of the smaller one is yours. Out of the circles is what is still unknown to us. Since mine is larger, I have to use the longer line to draw the bigger circle. That means I have more opportunities to face what is still unknown. And that’s why I myself have more questions than you do. The more you learn , the more questions you have. You will never learn enough ,you know.”
【小题1】The learned man drew two circles to show _____.

Two strangers were sitting together in a plane . They were on a long journey . One of the men was a teacher . The other was a farmer .
They sat without talking for a while , then the farmer said , “ Let’s do something to pass the time .”
“ What do you want to do ?” the teacher asked .
“ We can ask each other riddles (谜语 ),” the farmer said, “ You start.”
“ Let’s make the rules first ,” the teacher said . “ And to make the game more interesting , let’s play it for money . If we don’t know the answer to the riddle , we have to pay a dollar .”
The farmer thought about this for a while , then he said , “ That’s not fair（公平 . You are a teacher , an educated ( 受过教育的) man . You know more things than I do . I am just a farmer .”
“ That’s true ,” the teacher said , “ What do you think we should do ?”
The farmer said , “ If you don’t know the answer to a riddle ,you pay me 100 dollars .If I don’t know the answer to the riddle , I’ll pay you 50 dollars.”
The teacher thought for a while , then he said , “ OK. That’s fair . Who’ll go first ?”
“I will ,” the farmer said . “ Here’s my riddle . What has three legs when it walks , but only two legs when it flies ?”
The teacher thought and thought , “ What has three legs when it walks, but only two when it flies ?” Then he said , “ That’s a good one . I don’t know the answer .” He gave the farmer 100 dollars and said , “ Tell me the answer . What is it ?”
“ I don’t know , either .” The farmer said , and gave him 50 dollars .
【小题1】At first the two men sat there without talking because ________ .