You can tell a lot about people by looking at their hair – not just whether they brush, spray or blow-dry. Scientists have found a way to use hair to figure out where a person is from and where that person has been. The finding could help solve crimes, among other useful applications.

    Water is central to the new technique. The liquid makes up more than half an adult human's body weight. Our bodies break water down into hydrogen(氢) and oxygen. Atoms of these two elements end up in our tissues, fingernails, and hair.

    But not all water is the same. Hydrogen and oxygen atoms can vary in how much they weigh. In the case of hydrogen, for example, there are three types according to their weights. Each type is called a hydrogen isotope（同位素）. And depending on where you live, tap water contains different isotopes.

    Can hair record this information? That's what James R. Ehleringer, an environmental chemist at the University of Utah, wondered. To find it out, he and his colleagues collected hair from hair stylists in 65 cities across the United States. Even though people drink a lot of bottled water these days, the researchers have found that people's hair has the same isotopes as found in local tap water. That's probably because people usually cook their food with the local water.

    Authorities can now use the information to analyze hair samples from criminals or crime victims and narrow their search for clues. For example, one hair sample used in Ehleringer's study came from a man who had moved from San Francisco to Salt Lake City. As his hair grew, it reflected his change in location.

Let E-bikes Power New York's Transit Future

    Providence, R. I., just became the 13th city to develop an electric-assisted bike-share system, which runs or is developing bike-share networks in cities across the United States. Ironically, the Brooklyn-based company cannot operate in its hometown of New York City,due to the wrongheaded ban on electric bicycles.

    In many major cities in the U. S. and abroad, e-bikes are flourishing and helping to solve major urban challenges. Stockholm is adding 5, 000 e-bikes to its bike-share system. UPS is delivering packages in Hamburg using electrically-assisted cargo tricycles. And San Francisco's DoorDash food delivery service has found e-bikes to be the best mode to navigate heavy traffic and limited parking.

    In striking contrast, New York City insists e-bikes are banned under law. More than 900 e- bikes were seized and more than 1, 800 summonses（召回）were issued by the New York Police Department in 2017,following Mayor de Blasio's decision to limit e-bike usage, despite the fact that no data or records exist to show e-bike-related safety incidents.

    Who does the e-bike restriction hurt? The e-bikes seized in 2017 primarily belonged to food delivery workers, who are immigrants from Asia and Latin America. New Yorkers love their delivery: A new study from the New York City Department of Transportation found that more than half of city residents receive food deliveries at least a few times per month."

    In fact, the top three neighborhoods for e-bike summonses-the Upper East and West Sides and East Midtown-also consisted of more than 70% white residents. It's difficult to divorce the penalty of workers of color from the predominantly white, rich neighborhoods to whom the meals are delivered.

    It is true that the rush to maximize delivery numbers leads to higher speeds and potentially dangerous biking. To that end, the city should improve and enforce safe cycling and expand bicycling infrastructure to ensure safe passage for cyclists and pedestrians.

    Outside New York, cities and companies are finding that e-bikes are convenient, have low carbon footprints and require less space than cars on city streets. As New York City seeks to improve traffic, better air quality and encourage active modes of transportation, it is confusing that a mode that checks all of those boxes would be outlawed.

    The city must stop pedaling backwards on both workable transportation modes and the racially-charged policies surrounding them. It is time for New York City to embrace e-bikes as the very useful, worker-enabling, convenient and environmentally-forward mode that they are.

    If you think you have two left feet but would love to be a good dancer then why not try your hand at dancing?

    That's exactly what I did five years ago and I immediately fell in love with dancing. To me, dancing is a magical experience: I've become fitter, look younger and feel more confident. I enjoy it so much that I will never give up this healthy pastime.

    It's very sociable as well. You meet people and make new friends while dancing the night away. Haven't you heard stories about how dancing inspired new romances or rekindled (重燃) old ones? My friends Joe and Rena just had their big day a few weeks ago after they met each other at a Ceroc workshop some three years before.

    The word “Ceroc” comes from the French language. Without the complicated footwork, it is easier to pick up by beginners. Another good thing about Ceroc is that while it is a partner dance, you don't have to bring a dancing partner.

    Other popular styles of dancing in the UK include ballroom, belly dancing, lindy hop, salsa, tango and tap dancing, just to name a few.

    No matter what types of dancing you do, one thing is for sure: you will become fitter. For office workers like me, dancing is good cardio exercise after a long day sitting in front of the computer screen. It also strengthens your muscles, improves your coordination(协调) and increases your physical confidence.

    Few people will end up being queens of the dance floor. The aim is not to win a competition but to enjoy the interaction(交流). As long as you do the right moves, keep the rhythm and most importantly keep an encouraging smile to your dancing partners, you will always be a winner!

    Michael Jackson was on the road of performing when he was five years old. As is known to all, the road to fame and fortune is a long, hard one.

    Michael remembers those early years when he was young." My father was a machine operator," he explained, "and he worked at a steel plant. My mother worked at Sears, a big department store. But they were both musicians."

    Michael's father Joe Jackson realized his sons had a lot of talent, and he knew he could train them to become fine musicians. In those days there were plenty of music groups and some of them were very good. He knew if his sons were to stand out, they would have to be the best.

    Practice makes perfect. And the Jackson boys practised! Gradually the group took shape. Then word of this group began to get around. Thus Michael got a chance to do some solo(独唱) songs. In the following years, Michael was always on the top. One million records of his were sold in New Zealand, which has only a total population of three million!

    When Michael was eighteen, he entered another field of his career(生涯)—acting. "I plan to star in movies," he told his friends, "but of course, my first love is music."

    Michael wrote a lot of his own songs. "Songs came about in the strangest ways," he said, "I'll just wake up from sleeping and there is a whole song coming into my head. And then I put it down on the paper."

    Still, with all his success, Michael managed to keep his head calm. "I just do a different job from other people," he said, "but it doesn't make me think I'm better than other people."

    To be quite honest, his fans just love to hear and watch him!

    It is natural that young people are often uncomfortable when they are with their parents. They say that their parents don't understand them. They often think that their parents are out of touch with modern ways, that they are too serious and too strict with their children, and that they seldom give their children a free hand.

    It is true that parents often find it difficult to win their children's trust and they tend(倾向) to forget how they themselves felt when young.

    For example, young people like to act on the spot without much thinking. It is one of their ways to show that they have grown up and they can face any difficult situation. Old people worry more easily. Most of them plan things in advance, at least in the back of their minds, and do not like their plans to be upset by something unexpected.

    When you want your parents to let you do something, you will have better success if you ask before you really start doing it.

    Young people often make their parents angry with their choices in clothes, in entertainment and in music. But they do not mean to cause any trouble; it is just that they feel cut off from the older people's world, into which they have not yet been accepted. That's why young people want to make a new culture of their own, and if their parents don't like their music or entertainment or clothes or their way of speech, this will make the young people extremely happy.

    Sometimes you are so proud of yourself that you do not want your parents to say “yes” to what you do. All you want is to be left alone and do what you like. It is natural enough, after being a child for so many years, when you were completely under your parents' control.

    If you prefer to control your life, you'd better win your parents over and try to get them to understand you. If your parents see that you have a high sense of responsibility, they will certainly give you the right to do what you want to do.

An Art Class

When Kelly was twelve, she started taking classes at Miss Grace's School for Art. She didn't like it at first: the "novice artists"-the kids who hadn't really done art before-worked mostly with clay, and Kelly was a terrible sculptor. 

It wasn't until her third year that Kelly found something she was really good at-charcoal drawing （素描）. She loved watching the lines spread unevenly across the page as she moved the bits of charcoal back and forth over the paper. 

One day, Sophia. the best artist in her class, sat down and set up her easel （画架） next to Kelly. Kelly felt a sinking feeling in her stomach. She'd. actually found an art form that she enjoyed-and was good at--and now Sophia was going to outshine her again? Kelly fought back tears when Miss Grace entered the room. 

"Hello class, Miss Grace said. "We'll continue to work on the project today. What masterpiece would Sophia have come up with?

Kelly looked at Sophia's easel and she couldn't believe it--it was a mess! For a brief moment, Kelly couldn't actually believe her drawing was better than Sophia's. 

But then she looked at Sophia, who was watching Kelly with an anxious expression. "I…. I couldn't decide what to do, " Sophia said. "And you're so good. Sometimes I feel like my stuff is just so bad in comparison. 

Kelly looked to see if Sophia was joking, but she seemed completely serious. Now Kelly was shocked. "I'm not talented ... Miss Grace seldom praises me. You're the best one in our class!"

Sophia raised her eyebrows. "I might be a really good copier of the stuff, but I have no idea what to do when it comes to making up my own images. You are so great at making new things out of the old stuff. I've loved your works. "

"I've loved yours, too, Kelly said. 

"Well, definitely not this one, " Sophia said. 

Kelly smiled. "Maybe not right now. But if you move these lines up. . . "she said, pointing her finger on Sophia's paper. 

Sophia was quiet for a moment. "That's a great idea!" she said finally. 

Kelly smiled and turned back to her drawing, looking every so often at Sophia's work to see that she was taking her advice, down to the last line.