It is said that if you want to stay young, sit down and have a good think. This is the research finding of a team of Japanese doctors, who say that most of our brains are not getting enough exercise — and as a result, we are growing old unnecessarily soon.

    Professor Taiju Matsuzawa wanted to find out why otherwise healthy farmers in northern Japan appeared to be losing their ability to think and reason at a relatively early age, and how the process of aging could be slowed down. With a team of colleagues at Tokyo National University, he set about measuring brain volumes of a thousand people of different ages and varying occupations. Computer technology enabled the researchers to obtain precise measurements of the volume of the front and side parts of the brain, which controls functions like eating and breathing, does not contract with age, and one can continue living without intellectual on economical faculties. Contraction of front and side parts — as cells die off — was observed in some subjects in their thirties, but it was still not evident in some sixty-and seventy-year-olds. Matsuzawa concluded from his tests that there is a simple way to the contraction normally connected with age — using the head.

    The findings show in general terms that contraction of the brain begins sooner in people in the country than in the town. Those least at risk, says Matsuzawa, are lawyers, followed by university professors and doctors. White collar workers doing routine work in government offices are, however, as likely to have shrinking (萎缩) brains as the farm worker, bus driver and shop assistant.

    Matsuzawa's findings show that thinking can prevent the brain from shrinking. Blood must circulate properly in the head to supply the fresh oxygen the brain cells need. “The best way to maintain, good blood circulation is through using the brain.” he says. “Think hard and engage in conversation. Don't rely on pocket calculators.”

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

    Kenyon Scudder once told me a story about his friend, Michael. Michael happened to be on a train sitting next to a young man who seemed worried. Finally the young man told the friend that he was a convict (罪犯) returning home from a prison for away. What he did had brought shame on his family, and they had neither visited him nor written to him. He hoped, however, that this was only because they were too poor to travel and too busy to write.

    When he was set free he had written to tell them he wanted to go home. To make matters easy for them, however, he had asked them to put up a signal (信号) for him when the train passed their little form. If the family had forgiven (原谅) him, they were to put up a white ribbon (丝带) in the big apple tree near the railway. If they didn't want him back, they were to do nothing, and he would stay on the train, and go far away.

    As the train neared his hometown, his suspense became so great that he was afraid to look out of the window. He asked Michael to watch for the big apple tree. They changed seats. In a minute, Michael put his hand on the young convict's shoulder. “There it is,” he said, his eyes filled with sudden tears. “It's all right. The whole tree is white with ribbons.”

Teen Art Show

    Do you want to see your artwork displayed alongside other teens' artwork? Don't miss your opportunity! Showcase(在玻璃橱窗陈列) your paintings, sculptures, photographs and other artworks at the Environmental Educational Center. The show will provide an opportunity for artists to network, provide feedback and become a resource for others.

    Location: Environmental Educational Center

    Activity fee: $25

    Night Fishing

    Escape the night and join us as we fish at Desert Breeze Park. No experience needed. We will provide the fishing poles, transportation, the bait(鱼饵), to help you catch a fish and best of all, teens of 14 years and under do not require a license to fish.

    Location: Desert Breeze Park

    Activity fee: $ 22

    Overnight Snow Trip

    Join the City of Chandler in an exciting new trip! We will travel up to Camp Tontozona and enjoy great food and a campfire in the early evening. Snow play will be the highlight as we explore the snow-filled meadows(草地)of Woods Canyon Lake and sled down small hills in the area. You will be responsible for your own ski/ snowboard equipment.

    Location: Camp Tontozona

    Activity fee: $ 30

    Paintballing

    Come out and play paintball with all your friends! Join the City of Chandler as we go to Temp Indoor Paintball. This is a great way to join in the fun of paintballing for a low cost All equipment is included. Please wear old clothes because clothes can get dirty easily!

    Location: Tempe Paintball

    Activity fee: $ 28

    The search engine Google celebrated on Thursday the 110th birthday of the first Native American woman engineer. Google honored Mary Ross with a special Google Doodle on its homepage.

    Ross was born on August 9, 1908, in the state of Oklahoma. She was the great-granddaughter of John Ross, the longest—serving chief of the Cherokee Nation. Her work is considered important to the early stages of the age of space travel.

    Ross showed special abilities in math and science from an early age. As a student, she developed an interest in aviation, or the practice of flying aircraft. She went on to earn a master's degree in mathematics from Colorado State Teachers College, now called the University of Northern Colorado.

    During World War II, Ross began working for the Lockheed Aircraft Corporation as a mathematician. She earned a special certification in the field from the University of California in1949.Ross was later chosen to join Lockheed's top—secret Skunk Works team that worked on aircraft designs. The name refers to a group that is permitted to work independently on advanced projects. She was the only female engineer among the team's 40 members.

    Early on, she researched defense systems. By the late 1950s, her work centered on satellites and a series of space rockets called Agenda. The rockets were extremely important in the 1960s during the Apollo moon program.

    Ross also helped develop early design ideas for space travel between planets, including flyby space flights to study Venus and Mars. Ross retired from Lockheed in 1973.But she continued to give talks at high schools and colleges to encourage more women and Native Americans to study engineering. She died in 2008, a few months before her 100th birthday.

    Many celebrated Ross' life on social media. Twitter user Aaron Perez, for example, wrote: “Mary Ross was an engineer who pioneered in the field of satellites. I never would have known if it wasn't for the doodle. Women engineers deserve more recognition.”

Sharks have been swimming in the ocean for millions of years. They were on Earth even before dinosaurs! At the top of the world's ocean's food chain, sharks help keep the population of other ocean animals in balance. A large drop in the number of sharks can cause serious problems for all ocean animals. Saving sharks makes sense!

Many people are afraid of sharks. But most sharks are harmless. Only a small percentage of sharks are known to attack humans. It adapt (适应) well to new habitats and eat whatever is available. However, today, sharks are in trouble. Nearly one－third of the 400 shark species are in danger of extinction, largely due to over－fishing. Each year, tens of millions of sharks are caught and killed just for their fins. The fins are used to make shark fin soup.

Humane Society International (HSI) joined with the Jane Goodall Institute's Roots and Shoots program and Beijing Zoo to protect sharks. An exhibit at the zoo, "the Price Behind the Taste—Protect Sharks. Don't Eat Shark Fins", was designed to tell people that shark finning is cruel and unnecessary. It's hoped that the activity will help put an end to the practice.

Shark fin soup is also eaten in the United States. In fact, the numbers of some shark species in US waters have dropped 90 percent in the last 30 years. To slow the fall, laws against the sale of shark fins have been passed in several states, including Hawaii, Oregon, Washington, and California.

Barrington Irving made his historic flight and founded an educational non-profit-making organization.The secret,he believes,is having a dream in the first place,and that starts with learning experiences that inspire kids to build careers.

The moment of inspiration for Irving came in his parents' bookstore.One customer,a professional pilot,asked Irving if he'd thought about becoming a pilot."I told him I didn't think I was smart enough;but the next day he took me to the cockpit(驾驶舱)of the commercial airplane he flew,and just like that I was hooked."

To follow his dream,Irving turned down a football scholarship to the University of Florida.He washed airplanes to earn money and increased his flying skills by practising at home on a $40 flight simulator(模拟) video game.Then another dream took hold:flying alone around the world.He faced more than 50 rejections for sponsorship before convincing some companies to donate aircraft components.He took off with no weather radar,no de-icing system(除冰系统),and just $30 in his pocket.

After 97 days,26 stops and dozens of thunderstorms,he touched down to a cheering crowd in Miami."It was seeing so many young people watching and listening that pushed me into giving back with my knowledge and experience." Irving has been doing it ever since.He set up his non-profit-making organization,Experience Aviation(航空),aiming to increase the numbers of youth in aviation and science-related careers."We want to create chances for students to accomplish something amazing,"he notes.The most powerful educational tool is the example his own life provides.