The Silk Road is a name given to the many trade routes that connected Europe and the Mediterranean（地中海）with the Asian world. The route is over 6,500 km long and got its name because the early Chinese traded silk along it. Although silk was the main trading item, there were many other goods that travelled along the Silk Road between Eastern Asia and Europe. In the course of time, medicine, perfumes, spices and livestock（家畜）found their way between continents.

    The Chinese learned to make silk thousands of years ago. For a long time they were the only ones who knew how to make this precious material. Only the emperor, his family and his highest advisers were allowed to wear clothes made of silk. For a long time the Chinese guarded this secret very carefully. The ancient Romans were the first Europeans who became aware of this wonderful material. Trading started, often with Indians as middlemen（中间人）who traded silk with the Chinese in exchange for gold and silver which they got from the Romans.

    Travelling along the route was dangerous. The hot desert, high mountains and sandstorms made traveling a rough business. Most of the goods along the Silk Road were carried by caravans（商队）. Traders sometimes brought goods from one destination on the silk Road to another, from where the goods would be transported by someone else. Over the centuries people settled along the ancient route and many cities emerged. Later on there were fewer hardships to overcome, but by no means was it easy.

    Religion, languages and diseases also spread along the Silk Road. Buddhism, which originated in India, spread to China along this route. European traders probably brought the plague from Asia to Europe along the ancient road.

    In the early Middle Ages, traffic along the route decreased because of the decline of the Roman Empire. Trading along the Silk Road became stronger again between the 13th and 14th centuries, when the Mongols controlled central Asia. During the Age of Exploration the Silk Road lost its importance because new sea routes to Asia were discovered.

    Two deer jumped out in front of 16-year-old Amanda Floyd's car. She stepped on the brake, stopping the car just in time. But later, she started texting. Distracted (分心的)，Amanda turned left and right, then crashed into another car. Luckily, she wasn't in a real car--she was in a driving simulator (模拟器) at Roosevelt High School, Ohio, US. “I never really realized that cars make a turn that much," Amanda, a Junior, said. She added that she wouldn't text while driving anymore.

    The Ohio Department of Transportation (ODOT) and State Highway Patrol brought the simulator to the school. They said they wanted to help students learn about the danger of driving while drunk, while texting, or while talking on the phone.

According to the National Highway Traffic Safety Administration, distracted driving claimed 3,4501ives in2016 alone. Experts believe the actual figure is probably higher.

The simulator is basically a computer program. Like many computer games, it was a hit with the students. They lined up and crowded around to watch each other take turns. The simulator has a steering wheel! (方向盘) ,brake and gas pedal (油门踏板) . It is made up of three large computer screens on a table.

    Students choose a distraction, such as driving while drunk or texting. They always crash, of course. Then, they are pulled over by the police to be taught the bad results of their driving: how much damage they've caused, what their fine is, if anyone died in the accident, and if they're going to go to prison.

    "It teaches how to drive without being on the road," said Shante Thompson, 16. She had just crashed into a deer.

    ODOT spokesman Justin Chesnic said hundreds of kids have gone behind the wheel so far. He said even more have benefited from watching their classmates. "Driving is such a major responsibility, so take it seriously" he said. “Put away your cellphone. A lot of the accidents out there are because of distracted driving. It can not only change your life, but it can change someone else's life forever. The results are serious."

    Antaretica's ice-white environment is going green and facing other unexpected threats. Scientists say that as temperatures go up in the polar region, invading (入侵) plants and insects, including the flies, cause a major conservation threat.

    More and more of these invaders, in the form of larvae (幼虫) or seeds, are surviving in coastal areas around the South Pole, where the temperature has risen by more than 3℃ over the past three decades. Glaciers have retreated, exposing more land which has been occupied by mosses that have been found to be growing more quickly and thickly than ever before-providing potential green homes for invaders.

    “The common house flies are a perfect example of the problem the Antarctic now faces from invading species,” said Dominic Hodgson of the British Antarctic Survey. “It comes in on ships, where it exists in kitchens and then at bases on the continent. It now has an increasing chance of surviving in the Antarctic as it warms up, and that is a worry. Insects like the house flies carry bacteria that could have a deadly effect on native lifeforms.”

    The Antarctic has several native species of insects. Together with its native mosses, these are now coming under increased threat from three major sources: visiting scientists, increasing numbers of tourists and global warming. However, it is global warming that is the main driver of the greening of Antarctica.

    In 2015, more than 38,000 tourists visited Antarctica. “These tourists are often very careful about not leaving waste or having mud. But they could carry seeds or larvae on their boots when they set foot on the Antarctic,” said Hodgson.

    More and more invasive insects and plants have been found on the Antarctic and have required removal. “the insects and plants that are native to Antarctica have survived these for thousands of years,” said Hodgson. “We have got to act now if we want to save the environment.”

    According to new research from the University of Cambridge in England, sheep are able to recognize human faces from photographs.

    The farm animals, who are social and have large brains, were previously known to be able to recognize one another, as well as familiar humans. However, their ability to recognize human faces from photos alone is novel.

    The recent study, the results of which were published in the journal Royal Society: Open Science. Show the woolly creatures could be trained to recognize still images of human faces, including those of former President Barack Obama and actress Emma Watson.

    Initially, the sheep were trained to approach certain images by being given food rewards. Later, they were able to recognize the image for which they had been rewarded. The sheep could even recognize images of faces shown at an angle, though their ability to do so declined by about 15 percent – the same rate at which a human's ability to perform the same task declines.

    "Anyone who has spent time working with sheep will know that they are intelligent, individual animals who are able to recognize their handlers," said Professor Jenny Morton, who led the Cambridge study. "We've shown with our study that sheep have advanced face-recognition abilities, comparable with those of humans and monkeys."

    Recognizing faces is one of the most important social skills for human being, and some disorders of the brain, including Huntington's disease, affect this ability.

    "Sheep are long-lived and have brains that are similar in size and complexity to those of some monkeys. That means they can be useful models to help us understand disorders of the brain, such as Huntington's disease, that develop over a long time and affect cognitive abilities. Our study gives us another way to monitor how these abilities change," Morton said.

    When I was five or six years old, I remember watching TV and seeing other children suffer in other parts of the world. I would say to myself, "When I grow up, when I can get rich, I will save kids all over the world."

    At 17, I started my career here in America, and by the age of 18, I started my first charity organization. I went on to team up with other organizations in the following years, and met, helped, and even lost some of the most beautiful souls, tern six-year-old Jasmina Anema who passed away in 2010 from leukemia (白血病), whose story inspired thousands to volunteer as donors, to 2012 when grandmother lost her battle with cancer, which is the very reason and the driving force behind the Clara Lionel Foundation( CLF). We're all human. And we all just want a chance: a chance at life, a chance in education, a chance at a future, really. And at CLF, our mission is to impact as many lives as possible, but it starts with just one.

    People make it seem too hard to do charity work. The truth is, you don't have to be rich to help others. You don't need to be famous. You don't even have to be college-educated. But it starts with your neighbor, the person right next to you, the person sitting next to you in class, the kid down the block in your neighborhood. You just do whatever you can to help in any way that you can. And today, I want to challenge each of you to make a commitment to help one person，one organization，one situation that touches your heart. My grandmother always used to say, "If you've got a dollar, there's plenty to share."

    Homebuyers nationwide are watching housing prices go up, up, and up. "How high can they go?" is the question on everyone's lips.

    It's crazy, "said Tim, who is looking for a house near the beach. "In 1993, I bought a two-bedroom house in Venice for $70，000. My friends thought then that I was overpaying. Five years later, I had to move. I sold it for $230，000, which was a nice profit. Last year, the exact same house was for sale for S510, 000!

    It is a seller's market. Homebuyers feel like they have to offer at least 10% more than the asking price. Donna, a new owner of a one-bedroom house in Venice Beach, said, "That's what I did. I told the owner that whatever anyone offers you, I'll give you $20,000 more, under the table, so you don't have to pay your realtor(房地产经纪人) any of it. I was tired of looking.”

    Tim said, "Whether you decide to buy or decide not to buy, you still feel like you made the wrong decision. If you buy, you feel like you overpaid. If you don't buy, you want to kick yourself for passing up a great opportunity.”

    Everyone says the bubble has to burst sometime, but everyone hopes it will burst the day after they sell their house. Even government officials have no idea what the future will bring. "All we can say is that, inevitably, these things go in cycles," said the state director of housing. "What goes up must come down But, as we all know, housing prices always stay up a little higher than they go down. So you can't lose over the long run. Twenty years down the road, your house is always worth more than you paid for it.”