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.

    Thousands of years ago,in the south of ancient China,there lived Shennong,a man who had an ox head and human body.Seeing that local people were suffering from disease,he built ladders and houses on a high mountain to store hundreds of medical plants.To remember him,people named the place shennongjia.

    The legend(传说）makes Shennongjia in Hubei an inciting place for tourists.Traveling there is a unique experience,as you can see sceneries of the four seasons from different altitudes(海拔）.“When the bottom of the mountain is summer,the top is spring and while the foothill is autumn,the top is covered with ice,”local people say of the special climate of Shennongjia.

    Shennongjia is also home to 5,000 species of animals and plants.Many animals in danger live there,such as the golden monkey,the clouded leopard and the Asian black bear.

    One interesting and mysterious(奇妙的）thing about Shennongjia is its legend of wild men.Some people once claimed that they saw big prints or big-foot creatures.Yet so far,scientists haven't proved it is true and some say they are just bears.

    The beautiful place has recently received a new title.On July 17,2016,Shennongjia Forestry District was added to United Nations World Heritage list as a natural site.Chins now has 50 world heritage sites(遗址），second only to Italy in the world.

     Kumar and his two friends built a robot and named it Athena. They would go for Battle of the Bots--the city's biggest robot competition, and it would start in two days. The winning team would get $5,000.

     "How are we going to beat (打败) the Cougars?" asked Alex. The Cougars was the team that won the last two years' competitions.

    Kumar said, "The Cougars always build a big and strong (强壮的) robot. But usually their robot isn't very fast."

    "Our robot is fast," Alyssa said.

    "Yes!" Kumar said. "Don't worry. I have a plan for how to do it." Kumar told the group his plan and they began to work.

    Two days later, the competition began. Kumar said to his friends, "I' m sure the plan will work and Athena will win. Just wait and see."

    Athena won all of her first battles (较量). The Cougars' big, strong robot, The Avenger, did well, too. By the end of the day, The Avenger and Athena were the only two robots left in the competition.

    Soon the battle between Athena and the Avenger began. The Avenger lunged (猛扑) for Athena, but the small robot was too quick for him. Athena went behind The Avenger and, before the larger robot had time to turn, Athena hit (攻击) him from behind. The Avenger fell" down and couldn't move.

    The three friends all jumped up excitedly. "Now it's time for the real question," said Alex“      ”

    Vienna is a beautiful old city on the River Danube in the center of Europe. It's the capital city of Austria and the center of European classical music. In the 18th century a lot of musicians came to study and work in Vienna.

    In the Strauss family, there were two composers called Johann Strauss: the father and the son. The father, Johann Strauss the elder, wrote and played music for traditional dances, called the waltz. His dance music made him famous all over Europe. The son, Johann Strauss the younger, was also very successful and popular. He wrote over 150 waltzes. In 1867 he wrote The Blue Danube waltz.

    Mozart was another very important composer. He was born in Austria in 1756. Before he was six, he played not only the piano but also the violin. His family took him around Europe and he gave concerts in many cities. He wrote hundreds of wonderful pieces of music. But he became very poor and died in 1791 when he was only 35. Like Johann Strauss, father and son, he was a great European musician, and many people still think his music is perfect.