Millions of children in the United States go to summer camps. Some go to play outdoors at traditional camps in the woods, in the mountains or on lakes. But families now have many choices of special camps. These can be in the middle of nature or a big city. Special camps offer young people the chance to learn about different subjects: Anything from space exploration to business to medicine.

    In technology camps, one subject that children can learn about is video game design. They learn how to use computer programmes to create games of their own. One programme that teaches video game design is called Cybercamps. Children can learn how to design their own virtual(实际上的) worlds to set their video game in. Then, they programme their own rules and objects into the game.

    Cybercamps also offers courses in robot building and Web design. A recent story in the Washington Post described how one child made a robot that could sing a song. Another made a robot that could follow a black line drawn on a piece of cardboard. Also, children can learn how to make Web sites. One child made a site for pokeman, one of his favourite cartoon shows.

      The next time you look up at the sky and see a cloud that looks like Mickey Mouse or your favorite fruit, look again. It may not be a cloud, but a Flogo -- a logo that flies. It's a new form of advertising in the sky that's never been used before. It's a different way to market your products, logos, and events.

     These funny logos are made with soap bubbles （肥皂泡） mixed with a little helium gas （氦气） ,which makes them lighter than air and float in the sky. Special machines are used to make these new funny Flogos. The machine, which can be rented for $ ,500 a day, can make a Flogo every 15-5 seconds.

      Flogos can fly much higher or lower if needed. They can last from a few minutes to an hour anywhere in the sky, depending on the weather conditions. Though they can fly up to 0, 000 feet, they usually float around at 300- 500 feet. Flogos are only white now, but people hope to have more colorful Flogos in the near future.

     Flogos are Green, 100% environmentally safe, because the soap used to make the Flogo comes from plants and leaves. So this fun way of advertising is healthy and good for the environment.

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    Both seasonal flu, a disease like a very bad cold, and much larger pandemics, like the one caused by H7N9（禽流感） in 2013, are the result of a race between the flu virus  and the immune system which can protect people from illness. Here's how it works.

    Viruses, which cause pandemics, have two important proteins "haemagglutinin(H) and neuraminidase(N).H helps the virus go into a cell .N helps new virus break out of that cell .They are parts of a virus that may be known and dealt with by the immune system

    A flu virus attacks a host cell in order to reproduce itself. But the virus created out of it is quite different now. The virus's genetic material is copied with low fidelity. That difference produces virus which immune system does not always know and deal with immediately. Each year's seasonal virus is therefore a little bit different, and thus requires an updated vaccine to prevent people from getting that disease.

    Pandemics viruses have bigger changes in this process .Many hosts' defences are unprepared for such big changes, which happen three or four times a century .The 1918 pandemics was caused by viruses carrying H1 and N1.Anotber two pandemics in 1957 and 1968 were caused by viruses carrying H2and H3 together with N2.They are numbered by scientists. Much of this change goes on outside humans. A flu is usually from sick binds. Sometimes a bird-flu appears with materiel that enable it to spread among people .The H7N9 is recently worrying scientists in the health center.

    The flu virus sometimes jumps directly from a bird(often a chicken) to a person, but more usually passes through a pig The cells in bird and human are built differently, It means us that the virus needs different sets of material to attack them .Pig cells have features of both so that it can act as a platform in which the virus can fit from one to the other .Even after it has made humans ill, a virus cannot go ca to cause a pandemic unless it also gets the ability to pus easily between people, Luckily, this is something H7N9 has yet to do.

    The unknown world's mystery

    The sea is the biggest unknown part of our world. It covers about seventy-one percent of the earth. There is still much to be discovered about this huge part of water. If the waters of the ocean could be removed, the sea floor with its wide valleys(峡谷), tail mountains and long rivers in the sea would be a special sight.

    Tourism under the deep blue sea

    From tourist submarines(潜艇) to underwater dining, undersea tourism is making a big splash.

    Tourists can now explore(探索) the world under the sea without ever getting wet.

    Tourist submarines

    The popularity of submarine tours has grown fast during these years. Now, submarine tours have been on in more than 20 places worldwide, including the waters around Okinawa and Taiwan's Green Island. The submarines carry nearly 2 million tourists each year. Large windows give passengers special views as the submarines explore colorful coral reefs and sunken ships. Most one-hour tours cost about $ 80.

    Underwater dining

    For a more fantastic experience, tourists can enjoy fine dining under the sea. In 2016 the Hilton Maldives Resort & Spa opened the world's first underwater restaurant, Ithaa. Tourists walk down a staircase into the restaurant, which rests 35 feet in the Indian Ocean. You can have a great ocean view. But this excellent view doesn't come cheap. The dinner costs about $ 400 per person. Be sure to book it early, too, The restaurant seats only 14 people.

    When we think of paper, we think of newspapers and books. But there are many other uses. Only half of the world's paper is used for books and newspapers.

    Paper is very good for keeping you warm. You have perhaps seen homeless men sleep on a large number of newspapers. In Finland, it is sometimes-40℃ in winter. The farmers wear paper boots(靴子)in the snow. Nothing could be warmer.

    Each year, more and more things are made of paper. We have had paper cups and plates for a long time. But now we hear that chairs, tables, and even beds can be made of paper. Besides paper boots and shoes, you can wear paper hats, paper dresses, and paper raincoats. When you have used them once, you may throw them away and buy new ones.

    The latest use of paper seems to be paper houses. These are not small houses for children to play in, but real, big houses for people to live in. You can buy a house with three rooms for about 500 dollars. You can put it up by yourself in a few hours, and you can use it for about five years.