After I mastered my first (协奏曲) at age 14, my parents decided to get me a nice violin. I tried out dozens of instruments before I found my match: a German violin. It was beautiful, but what I liked best about it was its voice. Confident and strong, it was everything I longed to be.

    I'm not sure how much that violin cost, but my parents made me promise never to let it out of my sight. They didn't understand that dragging a large violin case ran counter to my daily middle school task of being invisible (看不见的). I was a strange, absent-minded kid. When I spoke up in class, my comments brought confused silence from teachers and wild laughter from students. Like a deer in a wolf pack, I tried to be quiet and still.

    In contrast, my new violin was almost shockingly loud. Together, we could drown out the rest of my middle school orchestra(管弦乐队) — which was encouraged, since the other kids made sounds like cats' crying. For one glorious hour every day, I was showered with attention. Everyone wanted to hear what I had to say.

    Between classes, I bent under the combined weight of my violin case and a backpack filled with books. My posture suffered, but my confidence grew. With my violin by my side, I found my voice. More and more, I contributed to class discussions and even made a couple of friends.

    Today, I'm just an amateur violinist with a regular day job. As I sit in my community orchestra, sometimes I feel jealous(嫉妒的) my fellow musicians' instruments with their elegant voices. I may not be the best violinist around, but at least I'm still the loudest.

    A new study suggests that the more teenagers watch television, the more likely they are to develop depression (忧郁) as young adults.

    The researchers used a national long-term survey of adolescent health to survey the relationship between media (媒体) use and depression. They based their findings on more than 4,000 adolescents who were not depressed when the survey began.

    As part of the survey, the young people were asked how many hours of television or videos they watched daily. They were also asked how often they played computer games and listened to the radio. Media use totaled an average of five and one-half hours a day. More than two hours of that was spent watching TV.

    Seven years later, more than seven percent of the young people had signs of depression. The average age at that time was twenty-one. The researchers say they did not find any such relationship with the use of other media such as movies, video games or radio, etc. But the study did find that every extra hour of television meant an eight percent increase in the chances of developing signs of depression. Young men were more likely than young women to develop depression given the same amount of media use.

    Last December, a popular magazine published a study of activities that help lead to happy lives. Researchers from the University of Maryland found that people who describe themselves as happy spend less time watching television than unhappy people. The study found that happy people are more likely to be socially active, to join in outdoor activities and to hang out with friends.

    Mom noticed that something was wrong when I started getting so thirsty. I'd have a lot to drink before bed, which was unusual for me. One time, I opened a big container of apple juice and kept refilling my glass. Before I knew it, I'd drunk the entire container! My mom called my doctor. I then had a few blood tests, and the results were certain — I had diabetes (糖尿病), which meant that the amount of sugar in my blood was very high. That can be dangerous, so I had to learn how to control my blood-sugar level.

    My eating habits had to change in a big way. With diabetes, I can't eat a lot of sugar or carbohydrates (碳水化合物). I have to figure out exactly how much sugar I plan to eat, and then I get an injection of insulin (注射胰岛素) before the meal to help my body process the food. Also, I test my blood-sugar level often. I'm always trying to keep my blood sugar at a healthy level. The level can drop when I exercise, but that doesn't keep me out of gym class or off the basketball court — I just keep some juice boxes around to boost my blood sugar if I need to.

    It's a lot of work and not a lot of fun to keep track of everything, but I've gotten used to my new habits. I was a little scared at first because I wasn't sure how my life would change. Once I knew what I needed to do, though, it wasn't a big deal. My life is different now from what it was before, but it has become completely regular to me.

    You may hear about some people who have walked on the moon. Of the outstanding astronauts listed below, who do you think was the most influential in human's history?

Pete Conrad (Apollo 12)

    Because of his dyslexia（阅读障碍）, Pete always failed in his study and had to leave school. Then his father sent him to Darrow School, where he performed so well that he won a Naval Reserve Officers Training Corps (NROTC) scholarship. He took the NASA's test, but his dyslexia ruined the opportunity.

    It was because of Alan Shepard's persuasion that Pete decided to apply again for NASA. He was chosen as the commander of Apollo 12. He landed on the moon on Nov 19, 1969 and spent 31 hours there.

Neil Armstrong (Apollo 11)

    Armstrong's biggest moment came in 1969, when he was chosen for NASA's first manned lunar mission (登月任务), along with Edwin Aldrin and Michael Collins. On July 21, 1969, he set foot on the surface of the moon. which made him the first human to do so. He stayed on the moon for 21 hours. After returning, Armstrong became an international star and was honored worldwide.

John Young (Apollo 16)

    Young was made the commander of Apollo 16, which landed on the moon on April 16, 1972. He spent two days and 23 hours on the moon. Young retired from NASA after serving for around 42 years, which made him the man ever to work for NASA for the longest time.

Edgar Mitchell(Apollo 14)

    Edgar was selected by NASA in 1966, and was later made the lunar pilot of Apollo 14. He followed his commander Alan Shepard onto the moon, staying there for 1 day and 9 hours. Edgar has expressed his firm belief that UFOS belong to other planets. He also firmly believes that American government is in possession of some “recovered alien bodies.”

    In March 2008, I told my friends: I was going to shut down my law practice and travel around the world in a year. What's more, I'd do it without taking any flights or making a single advance (预先的) reservation. Some friends offered support and encouragement, while others were doubtful. Once I'd said the words, there was no turning back. It took months to shut down my law practice and get things in order.

    There really wasn't any great reason why I wanted to circle the world. I simply wanted to do something fun and different. When I had this plan, I didn't plan for it to lead to a life on the road forever. I was planning to come back, open a new law practice and write a hugely successful book about my travels. Before I left, I started a travel blog, which served as a way to take notes for the book.

    Once I set off on my trip in December 2008, I found that travelling without using planes was not easy. It took seven days and nights on trains to get from Moscow to Beijing. Sometimes, I wouldn't see a village or a human being for 10 hours. I had a whole cabin to myself from the second day of that journey.

    It turned out that travelling with no reservations was far less difficult than I had imagined. Pulling into a city on a bus with a bag, looking in a guidebook for a few suggestions of accommodations (住宿), and then finding an empty room was never a problem.

    Soon after I started this adventure, I realised that my return to the US would be temporary (暂时的). About three months into my journey, I realised that I didn't want to go back to my old life. The world is so wonderful and I wanted to see as much of it as I could.

    Some educators told us that more years of school could help students get higher scores on intelligence tests. That was a finding of a study of teenage males in some countries. Now, another research shows that physical activity may help students do better in their classes.

    The research comes as educators in some countries are reducing time for activities like physical education. They are using the time instead for academic(学术的) subjects like math and reading. The studies appeared between 2008 and 2014. They included more than 55,000 children, aged 6 to 18.

    Amika Singh: "According to the results of our study, we can conclude that being physically active is beneficial for academic performance. There are, first, Physiological explanations, like more blood flow, and so more oxygen to the brain. Being physically active means there are more hormones(荷尔蒙) produced like endorphins(内啡肽). And endorphins make your stress level lower and your mood improved, which means you also perform better."

    Also, students taking part in organized sports learn rules and how to follow them. This could improve their classroom behavior and help them keep their mind on their work.

    The study leaves some questions unanswered, however Ms Stash says it is not possible to say whether the amount or kind of activity affected the level of academic improvement. This is because of differences among the studies.

    The researchers said they found only two high­quality studies. They needed more high­quality studies to confirm(证实) their findings. They also pointed out that "results for other parts of the world may be quite different".

    Still, the general finding was that physically active kids are more likely to do better in school. Ms Singh says schools should consider that finding before they cut physical education programs. Her paper on "Physical Activity and Performance at School" is published in the Archives of Pediatric and Adolescent Medicine.