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    The World Health Organization says the widespread use of sugar in food products and drinks is a major concern in many areas. So WHO officials are calling on governments to require taxes on sugary drinks in an effort to limit their usage and popularity. The officials believe the taxes also would reduce the risk of health problems resulting from obesity.

    Obesity is a condition in which the body stores large, unhealthy amounts of fat. Obese individuals are considered overweight. A new report says that in 2014 more than one-third of the adults in the world were overweight, and 500 million were considered obese. The United Nations agency estimates that in 2015, 42 million children under age 5 were either overweight or obese. It says that number represents an increase of about 11 million during the past 15 years. Almost half of these boys and girls live in Asia and one-fourth in Africa.

    The U.N. agency blames unhealthy diets for a rise in diabetes cases. There are 422 million cases of the disease worldwide. WHO says 1.5 million people die from it every year. It says the use of sugar in food products, like sugary drinks, is a major reason for the increase in rates of obesity and diabetes.

    Temo Waqanivalu is with the agency's Department for the Prevention on Non-Communicable Diseases. He told VOA hat taxing sugary drinks would reduce consumption and save lives. Waganivalu noted that Mexico enacted a 10 percent tax on sugary drinks in 2014. He said by the end of the year, there was a 6 percent drop in the consumption of such drinks. Among poor people, the number of people who consumed sugary drinks dropped by 17 percent.

    The WHO says people should limit the amount of sugar they consume. It says they should keep their sugar intake to below 10 percent of their total energy needs, and reduce it to less than 5 percent for improved health.

    The computers changed our lives in the 1980s, the Internet changed our lives in the 1990s, and the robots will change our lives in the new century.

    Do you think there will be robots in people's homes? It's not a dream that every home will have a robot.

    Now, robots are not only able to help people do the housework, they can also help the doctors do the difficult operations, play chess with people, play the piano and so on.

    A new cooking robot is used in Beijing. It can cook all the dishes on the menu, you only need to wait two to four minutes. In the future, the robot will be a nurse, a security guard, or a partner in your life.

    Experts believe robots will be used everywhere from the industrial robots to service robots. In the future, robots will become part of the family, and provide close service for people. We all look forward to the new robot age.

    The Golden Gate Bridge in San Francisco, California is one of the world's most beautiful bridges. It is also one of the most visited places in the world. Vehicles(车辆)cross the bridge an average of 41 million times each year. More than 1800 hundred million vehicles have used the bridge since it opened more than 70 years ago.

    The bridge was painted "International Orange" because that color went well with the natural surroundings. The color also is easier to see in the heavy fog that often covers the area. But the Golden Gate Bridge was not named for its orange color. It was named for the body of water that it crosses，the Golden Gate Strait.

    The Golden Gate Strait is the entrance to the San Francisco Bay from the Pacific Ocean. The Golden Gate Bridge links the city of San Francisco with Marin County, California.

    Planning for the bridge began in the 1920s when the area around San Francisco was growing. People living in the area needed another way to get to the city besides small ferries(渡船).

    Joseph Strauss was the chief engineer for the project. Work began in 1934. Mr. Strauss demanded the strongest safety protections in the history of bridge building. These included the first use of "hard hats" to protect the workers' heads and special glasses to protect their eyes.

    A special safety net was suspended(挂)under the bridge. This net saved the lives of 19 men during the construction. However，11 other workers were killed when they fell from the bridge through the net. Still，this was a new safety record for the time.

    The Golden Gate Bridge opened in 1937.It extends 1280 meters across the water. The total length is 2737 meters. It was the largest suspension bridge(吊桥)in the world until 1964.That is when the Verrazano Narrows Bridge opened in New York City. Today，the Golden Gate Bridge is the ninth longest suspension bridge in the world.

    They still bite, but new research shows lab-grown mosquitoes are fighting dengue fever — a dangerous disease that they normally would spread. Dengue infections appear to be dropping fast in communities in Indonesia, Vietnam, Brazil and Australia that are filled with the specially grown mosquitoes.

    Researchers first injected (注射)mosquito eggs with Wolbachia bacteria that's common in insects and harmless to people in a lab. Infected females then pass the bacteria on through their eggs. Releasing enough Wolbachia carriers, both the females that bite and the males that don't, allows mating(交配)to spread the bacteria through a local mosquito population.

    Rather than using chemicals to wipe out pests, "this is really about transforming the mosquito," said Cameron Simmons of the nonprofit World Mosquito Program, which is conducting the research.

    The first success came from Australia. Mosquitoes carrying Wolbachia were released in parts of North Queensland starting in 2011, and gradually spread through the local mosquito population. Dengue is spread when a mosquito bites someone who is infected, and then bites another person, but somehow Wolbachia blocks that — and local spread has nearly disappeared in those North Queensland Communities, Simmons said.

    The studies are continuing in other countries. But the findings, presented at a meeting of the American Society for Tropical Medicine and Hygiene, suggest it's possible to turn at least some mosquitoes from a public health threat into annoying biters.

    The work marks "exciting progress," said Michigan State University professor Zhiyong Xi, who wasn't involved with the project but has long studied how Wolbachia can turn mosquitoes against themselves.

    More research is needed, specialists cautioned. "The results are pretty exciting — strong levels of reductions — but there clearly are going to be things to be learned from the areas where the reductions are not as great," said Penn State University professor Elizabeth McGraw.

A planet the size of Jupiter has been discovered and it is one of the hottest ones known to us. This has made scientists think about how planets are formed.

Planets such as Earth have more oxygen than carbon, but what if the composition（组成）is just the opposite? This is a question opened up by a recent discovery of a diamond planet by US and UK scientists. The planet is 1200 light years away from Earth and was observed using NASA's Spitzer Space Telescope. Dr Marek Kukula explained that researchers initially used the Super WASP(Wide Angle Search for Planets) robotic observatories operating continuously, all year around. They detected the planet, then it was observed with the Spitzer Space Telescope, which detected the heat coming from the planet, and from that heat signature they can tell what this planet is made from.

The planet is very different to Earth. "It's giant planet," explains Dr Kukula, "a gas planet, a bit like Jupiter in our solar system. But the interesting thing that they've discovered is that it has a very different composition to the planets in our solar system. This planet has more carbon than oxygen." This suggests that there is more than one way to make a solar system and the range of planets in the universe could be much wider than previously thought.

Dr Kukula says that if there are smaller planets in the same solar system with a similar composition, rich in carbon, their rocks could be rich in minerals such as carbon and diamonds, unlike Earth which has silica (硅石), the sand that rocks on Earth are made from. "This is where this diamond planet idea comes from; they haven't actually detected a diamond planet yet," explains Dr Kukula.it' s hypothetical (假设的), "but you can imagine strange landscapes with black graphite rocks lying around and the surface could be covered with sticky liquids instead of water".