Deisha walked up and down as she waited backstage. This would be her most important piano performance yet. At ten years old, she was the youngest performer in the recital (音乐演奏会). She had practiced playing her song more than 30 times that week. When she closed her eyes at night, the music played over and over again in her head.

    Now that the day had arrived, Deisha was not sure she was ready. She smoothed her hair and picked a piece of lint (绒毛) from the new dress that her mother had bought for her. She noticed that her hands were shaking. How could she play the notes of the song if her hands were shaking? She tried to concentrate on steadying (稳住) them, but they only shook more.

   Deisha's piano teacher, Ms Neal, walked up to speak to her. “I have something for you,” she said, putting a smooth black stone into Deisha's hand. “It's a special stone. There's no other one like it in the world. You've practiced so much, you don't need anything else.”

   The stage lights reflected off the rock. “Thank you,” Deisha said.

   When Deisha's name was called, she rubbed the stone, stepped onto the stage, and played better than ever. After her performance, she noticed that Ms Neal had a whole bag of black stones. “Why did you say this one was so special?” she asked.

   Her teacher responded, “Because, like your talent, it belongs only to you.”

    Do you suppose Darwin, one of the greatest scientists of all time, really did fools' (傻瓜的) experiments? Or did he do experiments that were so simple and basic (基础的) that other people just thought they were foolish?

    Sometimes, people think they already know the answer to a question or a problem．Sometimes, they really do know an answer, but without thinking it is important．

    Charles Darwin didn't just think he knew something．And, he believed all things could be important no matter how simple they seemed to be．

    Suppose you drop pieces of paper that are of exactly the same size and shape．If you drop them at the same time in the same place, they will fall in the same way．Now make one of the sheets of paper into a tight little ball and let it drop along with the other pieces．What happens? You have done an experiment that is so simple that you might think it couldn't be worth anything．

    But this simple experiment is important．It explains part of our present day understandings of physics (物理学) ideas that were worked out long ago by Galileo and Newton．And these understandings set aside some of ancient Greek (古希腊的) physics．

    The scientist sometimes stops to look at very simple things and to think very hard about them．Even the simplest idea, which we might think is foolish, can shake the foundations (基础) of science．

    Johnnie Martin was born in a worker's family. His parents lived a simple life, saving money for the day when they could send him to a good university. They had dreamed that their son could get a good job and live a better life. However, to Johnnie, school lessons seemed like a wall that was impossible to go through. They were not so easy for him.

    One day when he was in Grade 11, Johnnie went to the school psychologist's (心理学家的) office to ask for help. "I've been trying hard, but…" Johnnie was about to cry.

    The psychologist put his hand on the boy's shoulder, "People have different kinds of talents, Johnnie. There are painters, who were never able to learn math, and some day you will find what you are good at. When you do, you will make all of us very proud of you."

    Johnnie didn't go to university. He found a job in the garden in the town. Soon something amazing happened. People began to notice that Johnnie had what they called a "green thumb". The plants grew well and the roses were in bloom (花). People started to accept his advice for gardening (园艺).

    One day while he was walking, he found an unusual dirty land. He volunteered to make it into a garden. That afternoon he started the work, but he couldn't afford all the tools or the plants. People gave him young trees, rose-bushes, benches and many other things. Before long, it had become a beautiful little park.

    Today Johnnie is the head of the business in gardening. Wherever he and his men go, they spread beauty before the eyes of people.

    Once there was a king. He liked to write stories very much. He always thought that his stories were good, so he liked to show them to people. As people were afraid of him, they all said his stories were very good and they wanted him to write more for them to read. The king was so happy that he wrote many more stories.

    One day, the king showed some of his best stories to a famous writer. He wanted the writer to praise (赞美) these stories. But after reading, the writer said his stories were so bad that there was no need to waste time on it and he should throw them into the fire. The king got very unhappy and sent him to prison.

    After some time, the king set him free (释放) and ordered him to come to his palace (宫殿). Again he showed some of his new stories and asked what he thought of them. After reading them, the writer at once turned to the soldiers and said, "Take me back to the prison."