If you have spent any time living in or visiting a big city in China, you have most likely used the service that Didi provides. The convenient ride-sharing company, now known as Didi Chuxing, was praised last month by Fortune magazine. According to the magazine, it is changing the world with its environmentally friendly solution to getting around in major cities. As the magazine reported: “Didi concluded that last year its car-pooling services helped reduce total car trips in the country by 1 million a day, which saved 500 million liters of gas, cutting 13.5 million tons of carbon emissions (排放) per day.” The transport service was the only Chinese company to make the important magazine's list, and its influence can be felt in many parts of Chinese society.

    Didi is just one example of what is being called the “sharing economy”. The sharing economy is one in which regular people exchange goods and services, usually using an online marketplace. Other similar companies include companies that allow people to rent out their homes to strangers like Airbnb and Couchsurfing, and similar ride sharing services like Uber and Lyft.

    All of these services are possible partly because many people are realizing that they have underused assets in their lives. Millions of people around the world have started renting them out online to earn extra money. They rent their apartments while they are away for the weekend, lend people their cars for money and even sell their spare time.

    The sharing economy is the latest example of the Internet's value to customers. This model is now big enough for regulators and companies to have woken up to it. That is a sign of its great potential. It is time to start caring about sharing.

    It seems that the great desire among the young is to be popular. The desire to be popular can force you into looking and acting like everyone else. You can lose yourself in a sea of identical hairstyles and thinking styles.

    I was forced to think about popularity not too long ago in a talk I had with my daughter. Margy had to change schools when my busy work schedule made it necessary for me to move houses. I suppose that，for a girl in her teens，entering a new school is like spending a season alone in the tropical jungles. At least that's how Margy found it at first. However，as the school year drew to a close，one student after another came to her.I told Margy that I would have been more concerned if she had been an instant social success in her new school. Nobody can please everyone. If you try to do so，you will find values as lasting as soap bubbles blown into the air.

    Some teenagers claim they want to dress as they please. But they all wear the same clothes. They set off in new directions in music. But somehow they all end up listening to the same record. Their reason for thinking or acting in a certain way is that the crowd is doing it. They have come out of their cocoon into a larger cocoon.

    I know that it has become harder for a young person to stand up against the popularity wave. Our way of life makes a young nonconformist stand out like a Martian. These days there's a great barrier for the young person who wants to find his or her own path. But the barrier is worth climbing over. You may want to listen to classical music instead of going to a party. Well，go to it. Be yourself .Popularity will come with the people who respect you for who you are. That's the only kind of popularity that really counts.

    Webber is a labor economist. His latest research offers guidance on how to keep students on target to earn a degree from a college or university. Among his findings: It is important, whenever possible, for college students to complete their degree program in four years. Also, getting a part-time job is probably a good thing to help finance a college education. But too much time spent working on a job makes it less likely the student will graduate.

    One thing, Webber said, is financial aid that helps many students pay for college. Scholarships and other assistance generally stop after four years. So the cost of each additional year in school is likely to come almost entirely from the student and/or parents.

    But there are other reasons why taking more than four years is a problem, as Webber notes. It's because life gets in the way, other things happen. He means the longer you stay in college, the more likely that some unexpected event will affect your studies. It could be a loved one getting sick, a parent losing a job, or the student running out of money for college.

    Only about four in 10 graduated within four years. It is also important that students have enough time to complete their college classes, Webber added. His research suggests part-time work of 15 hours or less will not cause harm to the student's scholastic performance. But his research shows students who work 20 hours or more a week are about 15 percent less likely to graduate on time, or to graduate at all.

    His belief is that students active in college athletic programs would face the same problem. It is common, he said, for student athletes to spend 20 hours or more for training, travel and to compete against athletes or teams from other schools.

    The following are four famous malls in the world where you can not only purchase things but also enjoy entertainment.

    Mall of America (Minnesota, USA)

    This Mall has a theme park and a wedding church, where more than 5,000 couples have been married since its opening. The mall of America opened in 1992 and is the third largest mall in North America.

    The mall of America is the most visited shopping mall in the world, with more than 40 million visitors annually. Spending 10 minutes in every store would take shopper more than 86 hours to complete their visit to the Mall of America.

    Mall of the Emirates (Dubai)

    The mall of the Emirates is an entertainment and shopping resort located in Dubai. It offers a full range of shopping, leisure and entertainment facilities.

    This shopping center is home to over 450 retailers（零售商）and also features a complete range of entertainment options, including Ski Dubai, the first indoor ski destination in the middle East.

    West Edmonton Mall (Alberta, Canada)

    The fifth largest mall in the world and the largest in North America, it has the largest indoor water park, which has the biggest wave pool in the world.

    The mall has a theme park called Galaxyland, with a number of attractions, including a roller coaster. In addition, the mall has an indoor lake, which is home to four sea lions.

    The Dubai Mall (Dubai)

    The Dubai Mall is the world's largest mall in total area.

    The mall has 1,200 shops and houses an aquarium（水族馆）which earned the Guinness World Record for the world's "largest Acrylic Panel". The mall is also home to an ice rink（溜冰场）, a 250-room luxury hotel and 22 cinema screens, plus 120 restaurants and cafes. It's also famous for the unique "malls-within-a-mall" concept, with themed shopping area like Gold Souk, Fashion Island and The Grove, an indoor-outdoor streetscape with a fully retractable（可缩回的）roof.

So far this winter, a theater in the Alps has staged more than 60 unique concerts. Winter temperatures in the remote mountain village can drop high below zero. Performers wear down jackets and play ice instruments. In fact, almost everything from drums and guitars to horns and harps at the music festival is carved from ice even the stage the musicians play on. The audience sits on ice chairs and benches and claps their hands to listen, both to praise the performers and to keep themselves warm when the air flows through.

The musical instruments used were almost entirely made by an American ice artist, Tim Linhart. Since he created his first musical instrument out of ice more than a decade ago, he has already carved various ice instruments, including violins, violas, timber drum sets, xylophone, double bass, mandolin and cello. He also created his own large wind instrument, which uses the vibration of an ice tube to produce sound when the air flows through.

Linhart makes the different parts of the ice instrument and then uses a liquid mixed with snow to glue them together, with a metal support placed where the strings need to be. A violin can usually be made in two or three weeks, while larger instruments can take more time and efforts, sometimes taking months to make.

An ice instrument has a clearer sound than a wooden instrument. However, ice instruments are more easily broken or damaged than ordinary instruments. The temperature in the ice theater changes depending on the number of people in the audience. This also changes the temperature of the ice instruments, which in turn affects the 1 sound they produce. Musicians need to tune their instruments frequently during performances.

Although playing an ice instrument is not easy, Linhart believes that ice and snow are good materials for making instruments. The only downside is melting when the temperature is above freezing.

Martha Payne is 9 years old. She lives in a small community in Scotland. Martha is interested in the food at her school. She is interested in how good it tastes, and how healthy it is, and whether it contains any hairs. A few months ago, she started to write a blog about her school dinners. She photographed her school dinners, and then posted the pictures on her blog and told us what she thought about the food. Most days, she thought the food was OK, and on some days she thought it was really good.

Children in other schools, and other countries, started to read Martha's blog. Some of them left comments on Martha's school dinners. And some sent Martha pictures of their own school dinners, and Martha published these on her blog. Then Martha started to use her blog to raise money for a charity called Mary's Meals, which provides school meals for children in poor communities in developing countries.

And at this point, the officials who run the education system in the part of Scotland where Martha lives became aware of her blog. They didn't want publicity for the food in their schools. Perhaps they were afraid that people would start to criticize (批评) their school dinners and say that they were unhealthy. They said that Martha's blog had to stop.

Martha's head teacher told Martha the bad news, and Martha was sad and wrote a final blog post to say goodbye to her readers. The newspapers, the radio and the television all carried stories about Martha's blog. This was not at all what the officials wanted. A day later, they decided that Martha could continue writing her blog about her school dinners, and taking pictures of them.