Sonya and her family have been homeless since she was 3 years old. Over the years, they have moved more than 15times to different shelters around New York City. Moving around was hard on Sonya。At school, Sonya hid her homeless from teachers and other students. She didn't want to be treated differently from other kids.

    In sixth grade, Sonya discovered a way to deal with some of her stress. She began studying dance at her middle school. “IT was a way for me to express myself, instead of just holding everything in,”she explains. Soon, Sonya auditioned（试演）for a summer dance camp run by Alvin Alley, a famous dance company. She was accepted. “I was excited,”says Sonya.

    Dancing became an even more important part of Sonya's life in high school. But things were not going well for Sonya at school. Each time her family moved to a new shelter, Sonya often took care of her younger sisters and brothers. She helped them get ready in the morning and took them to school. They would be on time, but Sonya would be late.

    Worrying about her family kept Sonya from thinking about her own future. That changed the summer after 11^th grade. Sonya learned she would have to go to summer school to graduate. She became determined to succeed, no matter what. “It was a wake-up call,”she says.“I had to focus on school and on myself.”

    Sonya made up the work that she had missed, and finally graduated from high school. No one in her family had gone to college before. But in September 2015, Sonya enrolled in the State University of New York at Potsdam. She plans to become a doctor for kids and to teach dance to children who have disabilities.

    Scientists today are making greater effort to study ocean currents (洋流) . Most do it using satellites and other high-tech equipment. However, ocean expert Curtis Ebbesmeyer does it in a special way -- by studying movements of random floating garbage. A scientist with many years' experience, he started this type of research in the early 1990s when he heard about hundreds of athletic shoes washing up on the shores of the northwest coast of the United States. There were so many shoes that people were setting up swap meets to try and match left and right shoes to sell or wear.

    Ebbesmeyer found out in his researches that the shoes — about 60,000 in total — fell into the ocean in a shipping accident. He phoned the shoe company and asked if they wanted the shoes back. As expected, the company told him that they didn't. Ebbesmeyer realized this could be a great experiment. If he learned when and where the shoes went into the water and tracked where they landed, he could learn a lot about the patterns of ocean currents.

    The Pacific Northwest is one of the world's best areas for beachcombing(海滩搜寻) because winds and currents join here, and as a result, there is a group of serious beachcombers in the area. Ebbesmeyer got to know a lot of them and asked for their help in collecting information about where the shoes landed. In a year he collected reliable information on 1, 600 shoes. With this data, he and a colleague were able to test and improve a computer program designed to model ocean currents, and publish the findings of their study.

    As the result of his work, Ebbesmeyer has become known as the scientist to call with questions about any unusual objects found floating in the ocean. He has even started an association of beachcombers and ocean experts, with 500 subscribers from West Africa to New Zealand. They have recorded all lost objects ranging from potatoes to golf gloves.

    Listed below are the stories of women you may not know about, but definitely should.

    Hedy Lamarr

    Hedy Lamarr starred in many films. But her film career is far from her only noteworthy achievement; she was also a brilliant inventor. In 1942, she and composer George Antheil received a patent（专利）for a device that could change radio signal frequencies. The purpose of the technology was to keep military enemies from figuring out messages. But it did more than that - it laid a foundation for the wireless technology we use today.

    Maria Sibylla Merian

    Today, children can happily explain how a caterpillar（毛虫） tums into a butterfly. But there was a time when no one knew this. Until the 1670s, scientists thought that caterpillars and butterflies were two totally different creatures. Thanks to Maria, we know the truth about these beautiful winged insects. Fascinated by insects, she began collecting, studying and drawing them as a child. It was through her study of caterpillars that she discovered the truth about their life cycles. She published two volumes of naturalist research, which provide major contributions to the field of entomology（昆虫学）.

    Ada Lovelace

    Ada Lovelace, the daughter of celebrated British poet Lord Byron, wasn't a poet herself but the world's first computer programmer. We think of computers as a recent invention, but people were toying with the idea of "computing machines" in the mid – 19th century when Lovelace was alive. Lovelace's mathematical genius was apparent at a young age and caught the attention of Cambridge professor Charles Babbage, who was working to design early computing machines that would be able to quickly solve math problems. Lovelace wrote some suggestions as to how to program the machines to work out numbers.

    In addition to designing this early computer program, she was also the first to surest that these computers might be able to do more than compute. She imagined them doing almost everything, from producing images to composing music.

    Trees are useful to man in three important ways: they give him wood and other useful things, they give him cool places, and they help to stop drought and flood.

    Unluckily, in many parts of the world, man has not found that the third of these points is the most important. Man wants to make money from trees, so he has cut them down in large numbers, only to find that without them he has lost the best friends he had. And also, he is usually too careless to plant and look after new trees. So the forests slowly disappear.

    This does not only mean that man will have fewer trees. The results are even worse: for where there are trees, their roots break up soil-make the rain in-and also bind the soil, thus stopping it from being washed away easily; but where there are no trees, the rain falls on hard ground and flows away, causing floods and carrying away the rich top-soil. When all the top-soil is gone, nothing is left but useless desert.

    Unlike most other holidays, the history of April Fools' Day, sometimes called All Fools' Day, is not totally clear. The only point in time that can be agreed on as the beginning of this tradition was 1582, in France. Before that year, the New Year was celebrated for eight days, beginning on March 25th. The celebration reached the highest point on April 1st. With the reform of the calendar under Charles IX，the Gregorian calendar(公历，阳历) was introduced, and New Year's Day was moved to January 1st.

    However, because in those days communications were not as developed as they are today, many people did not receive the news for several years. Some people refused to accept the new calendar and continued to celebrate the New Year on April 1st. These backward people were considered "fools" by other people. They  were often sent on "fools" errands(徒劳无益的工作)  or were made the targets of jokes.

    This developed, over time, into a tradition of playing a trick on someone on the first day of April. The tradition eventually spread to England and Scotland in the eighteenth century. It was later introduced to the American colonies of both the Britain and France. April Fools' Day thus developed into an international fun feast, so to speak, with different nationalities specializing in their own kind of humor at the expense of their friends and families.

    Should Parents Teach Children How to Tweet?

    Social media is a seemingly endless source of concern for parents, with worries that it weakens their children's confidence and attention spans. But others counter that it could also be broadening their horizons.

    The latest round of worry was sparked by a study of the impact of social media use on 8-12- year-olds published by Anne Longfield, Children's Commissioner for England. The report focused on 32 children, who said they used social media to stay connected with friends and family and to have fun, by watching videos for example. But they also described pressures from constant contact, online comments that weaken their self-esteem, and the need to shape offline activities to make them shareable. "You see your friends going ice skating, partying or talking about how much revision they have done, and it can make you feel inadequate," says Bea, a junior school student from Bristol, UK. "It's just so hard to get away from."

    Children have to take risks on their journeys to adulthood, and desires to fit in and be popular existed before Mark Zuckerberg came along with Facebook. However, in previous generations these pressures came largely from people they knew, and they mostly stayed outside the home. Now the pressures could come from any one of the nearly 3 billion people online, and follow them from school to home, and can even continue through the night.

    The pressures do get on parents' nerves, among which the utmost concern is how their children can be protected from harms, given that social media is now integral to the way many young people interact. A good starting point is a basic understanding of childhood development milestones.

    Broadly, children have a high dependency on carers for security and guidance up to the age of 5, increasing independence and self-care from 6 to 11, and increasing autonomy and growing reliance on peers from 12-18 years old. Against this background, the suitability of social media for children of different ages should be considered respectively.

    According to Longfield's study, children should be taught about online safety from an early age, better before secondary school. There is growing evidence that efforts need to be extended to provide earlier guidance on less extreme but more common risks, including oversharing, low selfesteem, addiction and insomnia. The evidence suggests she is right. However, approaches that focus merely on the potential negatives are unlikely to work.

    "My school has tried to do a lot, but it often involves trying to drill into us how bad social media can be," says Bea. "People of my age really like social media, so I think a better approach would be if they said ‘Although it is good, here are some negatives'."