“ Ask not what your country can do for you--ask what you can do for your country.” It's a famous quote from US president John F, Kennedy's inaugural(就职) speech in 1961.

    Mark Zuckerberg, the founder of the social networking site Facebook, must agree with Kennedy. The 33-year-old American donated $100 million to the public schools in New Jersey, US.

    Who is this young billionaire? How did he make his fortune?

    Thirteen years ago, Zuckerber was a computer geek(怪才) at Harvard University. As a second-year student, he set up a website to put the “face books” --photos of incoming first-year students online. The website, where people were able to share personal information, was a success at once.

    Zuckerberg first opened Facebook to high school students and then to everyone. Greeting such as “Have you checked your Facebook page today?” and “Do your ‘friends' know what you ate for breakfast?” became a part of American life. Now Facebook is the most popular site in the world with 1.7 billion users.” I could have never imagined all of the ways people would use Facebook when we were getting started thirteen years ago,” Zuckerberg wrote in a recent blog.

    Zuckerberg's dream is to make the Internet a more connected place. The mission(任务)could become profitable for Facebook. The more people share information about themselves online, the more money Facebook will make selting advertising. Zuckerberg is already worth $34 billion, according to Forbes.

    Yet the billionaire keeps his own life out of the public eye. At the company, it is said that he sits among a sea of desks like hundreds of workers. A visitor to Facebook might not even spot Zuckerberg in T-shirt and jeans. He usually takes one two-week vacation each year with his wife Priscilla Chan, a Chinese American. On the weekends, it is reported that he roasts pig and goat in his backyard for friends and takes Chinese lessons.

    The Social Network, a movie based on Zuckerberg's story, came out in 2010. It became one of the most popular films of that year.

    My name's Nannan. I'm a student. I'm 11 years old. I'm in Class Five. This is my friend. His name is Tom. He's 12 years old. He's in Class Six. My favourite colour is red. His favourite colour is blue. We are not in the same(相同的)class, but we are good friends.

    Jack thought himself a basketball fan. He watched quite a lot of American NBA basketball games. Not only did he watch them, he spent much of his free time playing on the court too. Then came the final year of his middle school. All of his regular teammates stopped showing up on the court because they were simply too busy preparing for the high school entrance exam to play. He was, of course, under much stress himself, like everyone else. A good exam result meant a good high school; a mediocre(平庸的) score meant a mediocre school. Much was at stake.

    However, he loved basketball so much that he still found time to play, this time with a group of guys who were said to have skipped classes(逃课) before.

    Some of his teachers started worrying about him. They asked his mother to go to school to let her know that Jack was hanging out with problem kids. When his mother returned home that day, she wanted to talk to Jack. Knowing the purpose of her visit to the school, Jack though his mother would punish him for befriending those bad guys. To his surprise, his mother was not angry with him at all. She wanted to hear her son's side of story. So Jack told his mother about what he knew of Simon and Peter. Simon's parents were badly ill; Peter's father had lost his job. They both seemed to Jack to be normal kids. Jack's mother thought for a moment, and then went on to say that she was OK with her son playing with them and that she and her son should think of ways to help these kids. Soon Jack's mother introduced some part -time jobs to Simon and Peter, which they accepted. She believed in her son and cared about those who were less lucky.

    Jack's basketball friends and he have left for different places, but they still keep in touch. He knows Peter is now a manager of a local bank. Simon is currently a freshman at a university. Sadly, it is impossible to get together to play basketball again, but whenever they get on the phone, they talk about all the time.

    Life is full of surprises and you never know how things will turn out.

    Sir John Gurdon is a good example of this. As a boy, he was told he was hopeless at science and finished bottom of his class. However , the very same Gurdon shared the 2012 Nobel Prize in Medicine with Japanese stem cell (干细胞) researcher Shinya Yamanaka.

    Like so many scientists, Gurdon shows us where the power of curiosity and perseverance (坚持不懈) can lead.

    At the age of 15 in 1948, Gurdon ranked last out of the 250 boys at his high school in biology and every other science subject. Gurdon's high school science teacher even said that his dream of becoming a scientist was " quite ridiculous".

    In spite of his teacher's criticisms, Gurdon followed his curiosity and kept working hard. He went to the lab early and left later than anyone else. He experienced thousands of failures.

    "My own belief is that we will, in the end, understand everything about how cells actually work," Gurdon said.

    In 1962 ,Gurdon took a cell from an adult frog and moved its genetic( 基因的 ) information into an egg cell . The egg cell then grew into a clone(克隆) of the adult frog. This technique later helped to create Dolly the sheep in 1996,the first cloned mammal(哺乳动物) in the world.

    In 2006, Gurdon's work was developed by Yamanaka to show that a sample (样本) of a person's skin can be used to create stem cells. Using the technique, doctors can repair a patient's heart after a heart attack.

    "Luck favors the prepared mind," Gurdon told the Nobel Prize Organization. "Ninety percent of the time things don't work ,but when they do ,you have to seize(抓住) the chance. "