CHICAGO- Have you ever worked on your laptop computer with it sitting on your lap, heating up your legs? If so, you might want to rethink that habit from now on. Doing it a lot can lead to “toasted skin syndrome (症状)”, an unusual-looking spotted skin condition caused by long-term heat exposure (暴露), according to medical reports.

       In one recent case, a 12-year-old boy from California developed a skin discoloration on his left lap after playing computer games a few hours every day for several months. “He recognized that the laptop got hot on the left side; however, he did not change its position,” Swiss researches reported in an article published Monday in the journal Pediatrics.

      Another similar case is a Virginia law student who needed treatment for the spotted darkening on her leg. Dr. Kimberley Salkey, who treated the young woman, learned the student spent about six hours a day working with her computer placed on her lap. As Dr. Salkey later learnt, the temperature under the laptop could reach 51 degrees. That case, from 2007, is one of 10 laptop-related cases reported in medical journals in the past six years.

The condition can also be caused by overuse of heating pads (垫子) and other heat sources that usually aren't hot enough to cause burns. It's generally harmless but can also cause such permanent (永久的) skin darkening. In very rare cases, it can cause damage leading to skin cancers, said the Swiss researchers, Drs. Andreas Arnold and Peter Itin from University Hospital Basel. They do not mention any skin cancer cases linked to laptop use, but suggest, to be safe, placing a carrying case under the laptop if you have to hold it on your lap.

      Dr. Kimberley Salkey said that under the microscope, the affected skin is similar to skin damaged by long-term sun exposure.

      Major producers including Apple and Dell warn against placing laptops on laps or exposed skin for long periods of time because of the risks for burns. In the past, “toasted skin syndrome” has happened to workers whose jobs require being close to a heat source, including bakers and glass blowers, and in people who gathered near hot stoves to stay warm.

Dr. Anthony J. Mancini, chief at Children's Memorial Hospital in Chicago, said that it's unlikely that computer use would lead to cancer since it's so easy to avoid close skin contact (接触) with laptops.

    Many people are surprised when they find that the Internet was set up in the 1960s. At that time， computers were large and expensive. Computer networks didn't work well. If one computer in the network broke down， then the whole network stopped. So a few network system had to be set up. It should be good enough to be used by many different computers. If part of the network was not working， information could be sent through another part. In this way computer network system would keep on working all the time.

    At first the Internet was only used by the government， but in the early 1970s， universities， hospitals and banks were allowed to use it， too. However， computers were still very expensive and the Internet was difficult to use. By the start of 1990s， computers became cheaper and easier to use. Scientists had also developed software that made "surfing" the Internet easier.

    Today it is easy to get online and it is said that millions of people use the Internet every day. Sending e-mails is more and more popular among young people. The Internet has now become one of the most important parts of people's life.

    Since ancient times, human beings have looked up at the night sky. Comets (彗星) and meteors (流星) flying through the blackness were seen as signs from the gods. They were used to tell the future of human lives.

    In 2013, a meteorite shower hit an area in Russia. It injured around 1,200 people. In ancient times, this would have been a strange and terrible experience. Today, thought, science offers simple explanations for the occurrence (事件).

    Meteorites are small pieces of debris (碎片) that float around in space. Sometimes, they come near a planet, such as Earth. When they enter our atmosphere, they often heat up and become very bright. This is why they are sometimes called “fireballs”. They are usually made of metals, such as iron (铁), and other minerals (矿物). The Russian meteorites were stony, with iron making up 10 percent of them.

    Meteorite showers, such as that in Russia, happen when a large meteor enters the Earth's atmosphere and, due to heat, breaks up into small parts. Most of these are very small — smaller than a grain of sand — and so don't even make it to the ground. But others can cause a lot of damage.

    The meteor in Russia weighed 10 tons when it entered our atmosphere, and broke up about 20-30 miles (30-50 km) above ground. The sky was filled with bright lights and loud noises. Many windows were broken. The damage cost Russia around 206 million yuan.

    Have you ever wished that your life was like a reality TV show(真人秀节目)? Well, like it or not, things might be this way in the future.

    This is because of Google glasses. Glasses are the latest technology from Google. They have more exciting features(特征)than you could possibly imagine.

    For one thing, people who wear the glasses can shoot videos and record the sounds around them. So if your friend is wearing Google glasses, he or she can record your every move and broadcast live on the Internet for the world to see.

    There is a GPS system in the glasses. So if you get lost you can say" OK, Glass, where am I?", and it will find where you are and tell you where you need to 90.

    Google glasses are a bit like a helpful secretary. You can tell them what you want to write in an e—mail and they will type it for you.

    Since April 16, Google glasses have been on the market in small numbers. But by the end of the year anyone will be able to buy a pair for about 2, 500 yuan.

    Some people are not sure whether they find Google glasses cool or not. When someone is wearing Google glasses, it is not easy to see whether or not they are using them.

    In most parts of the world, many students help their schools make less pollution. They join environment clubs. In an environment club, people work together to make our environment clean.

    Here are some things students often do.

    No-rubbish lunches. How many lunch bags do you throw away after lunch? Environment clubs ask students to bring their lunches in bags that can be used again. Every week they will choose which classes make the least rubbish and report them to the whole school.

    No-car day. On a no-car day, nobody comes to school in a car including the students and the teachers. Cars give pollution to us, so remember:

    Walk, jump, bike, or run!

    Use your legs! It's lots of fun!

    Turn off the water! Do you know that some toilets can waste twenty to forty cubic (立方) meters of water an hour? In a year, that would fill in a small river. In the environment clubs, students repair those broken toilets.

    We love our environment. Let's work together to make it better.