How long is a year? Most people say a year is 365 days. It takes about 365 days for the earth to go around the sun. In fact, it takes a little longer for the earth to go around the sun. It needs 365 days, 5 hours, 48 minutes, and 46 seconds.

    If a year has only 365 days, what happens to the extra(额外的) 5 hours, 48 minutes, and 46 seconds? The answer is this: Every four years, we have another day. It's February 29, and we call this day " a leap day(闰日)".This kind of year is called "a leap year". A leap year has 366 days.

People born on February 29 are called leap-day babies, or leapers. There are about four million leapers in the world. When do they celebrate their birthday? Do they celebrate only once every four years? Some leapers celebrate the birthday on February 28, and others celebrate it on March 1. Think about it: A twelve-year-old leaper may have celebrated only three birthdays on the real day after he or she was born!

    Which year are leap years? Years that can be divided(除尽)by four are leap years. The year 2000 was a leap year. Then 2004,2008,2012,2016 were the next leap years. If you know a leaper, you must say "Happy birthday!" to him or her on the leap day, because you just have one time to do that every four years!

    Today there are robots working in factories. Some can help to build cars, and they do easy jobs over and over again. Few people will do such jobs in the future because they are boring, but robots will never get bored.

    Scientists are now trying to make robots look like people. Some robots in Japan can walk and dance. However, some scientists believe that it will be difficult to make them really think like people. For example, scientist James White thinks that robots will never be able to wake up and know where they are. But many scientists don't think so. They think that robots will even be able to talk in 25 to 50 years.

    Some scientists believe that there will be more robots in the future. These new robots will look very different. Some will look like people, and others might look like animals. In India, for example, scientists made robots that look like snakes. When buildings fall down with people inside, these snake robots can help look for people under the buildings. This was not possible 20 years ago, but computers and rockets also seemed impossible 100 years ago. We never know what will happen in the future!

    You may know several kinds of police, traffic police and street police. But have you ever heard of energy-saving (节能) police?

    A group of 22 new policemen went to work in Beijing. They went around the city to see the use of energy in hotels, office buildings, shopping centres and other public places. One of their aims is to make sure that these places have set their air conditioners (空调) no cooler than 26℃.

    They also set up a special phone hotline so that people can tell them which building doesn't follow the rule.

    "If everyone sets the air conditioner at 26℃, Beijing will save 400 million kilowatt-hours of electricity in one summer. That's one third of all the usage of the city in the season, said an advertisement."

    A show was held in Beijing last week on energy-saving technology (技术) and productions to introduce a green life to the public. Environmentally—friendly machines, like a machine that helps collect used bottles, have attracted lots of attention.

    "We want to tell people that there are some ways to protect the environment. Each of us can find effective (有效的) ways to do it in our daily life," said Liu Qianguang, an environmental engineer.

    If you're ever apart from your children, a new study says just talking on the phone will help just as much as a hug(拥抱).

    If you're a parent who spends long hours on the job, you probably feel sorry for spending so much time away from your kids. But the results of a new study show that a mother's voice alone can be just as comforting to an anxious child as physical contact(接触).

    In an experiment, researchers from the University of Wisconsin Madison asked a group of girls between the ages of 7 and 12 to solve math problems in front of judges—a stressful situation for anyone. Before the girls were set to give their answers, the researchers measured their levels of two hormones(荷尔蒙): cortisol, which goes up during stressful periods, and oxytocin, the "love" hormone, which goes down at the same time.

    After the girls finished the problems, some of them got to meet up with their mothers right away. The moms came in and hugged the girls. Another group of the girls didn't see their mothers, but received phone calls from them, in which their mothers told them how well they'd done. The final group had no contact with their mothers, but instead watched an animal movie, March of the Penguins.

    Finally, the girls' hormone levels were measured again. Although the movie was interesting, it did nothing to reduce the children's anxiety—but, surprisingly, both the physical contact and phone calls from their mothers had the same effect on reducing the girls' stress levels.

    So, no matter how old you are, if you're feeling stressed about something in your life, a phone call to Mom might be just the key to help you feel better.

    Cars make our lives more convenient. But they can also be a problem. For example, fossil fuel(化石燃料) cars mainly cause air pollution.

    To improve the environment, many countries are developing electric vehicles (EVs,电动车). Among them, China is taking a leading role and has created the world's largest EV market.

    Last year, over 40 percent of the 753,000 EVs sold in the world were sold in China, more than twice as many as the number sold in the United States.

    "Filling up a fossil fuel car with gas(汽油) is more expensive than charging( 充电) an electric car，" said Wu Hao，who bought an electric car this year.

    However, there are still some problems. It can be hard to find charging piles(充电桩) and the cars can't go far before needing to be recharged.

    Some of these problems are being solved. In 2014，China had 31,000 charging piles. Now China has the world's largest EV charging network, with more than 167, 000 charging piles in total.

    Developing EVs is one of many efforts that China has made to cut down pressure on its environment after the government promised to stop increases in carbon dioxide emissions(二氧化碳排放量) by 2030.

    "As China goes, so will the world's car industry," The Wall Street Journal said. China has taken a leading role in the world's electric vehicle industry.