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.

    You don't have to be a scientist to solve big environmental problems. One Dutch designer is finding creative ways to make a change—and he's inviting bikers to join him.

    Daan Roosgaarde, 38, is a designer from Holland. He uses creative ideas to improve city life. For his Smog (雾霾) Free Project, he designed a special tower that cleans air in Chinese parks. In Holland, he designed a shining bicycle path.

    Now Daan and his team are working with engineers at Chinese bike-sharing company Ofo to create a new product for public use. It's an air-cleaning machine connected to a bicycle and is part of the Smog Free Project. In smoggy weather, the machine would breathe in the air in front of the bike and blow out a stream of clean air toward the biker's face.

    It's no secret that air pollution is a big problem for China. In winter, it's common for thick clouds of haze (霾), caused largely by factory production, burning of coal and car emissions (排放物), to cover areas of China.

    In 2016, only one-fourth of Chinese cities met the country's air quality standards, according to a survey of 338 cities nationwide from the Ministry of Environmental Protection.

    "Of course one tower and a few bikes won't solve China's air pollution problem," Daan said, "But smog-free bikes are an exciting idea that will hopefully inspire communities to create greener cities."

    Many objects in the universe are invisible, but they send radio waves. The radio telescope* thus appeared, and it is considered one of the greatest inventions in the twentieth century. Reber built the world's first radio telescope in 1937. Ryle and Hewish developed radio telescope systems for the location of weak radio sources, and they shared the Nobel Prize for Physics in 1974.

    A radio telescope is usually made up of:

    One or more antennas to collect the radio waves. Most antennas are made in the shape of a dish to collect and reflect, the radio waves to the sub—reflector, in the same way as a curved mirror focuses visible light to one point.

    A receiver and amplifier to receive the radio waves from the sub—reflector, and make these weak radio waves strong enough to be recorded and turned into electronic signals. To make an amplifier sensitive enough, it is usually cooled to, very low temperatures (e. g. as low as —270℃）.

    A recorder to keep a record of the electronic signals. Most radio telescopes today keep the signals to the computer's memory disk for astronomers to analyze later.

    Radio wavelengths are much longer than those of visible light, and the radio waves from deep space are always weak. To catch Radio wavelengths are much longer than those of visible light, and the radio waves from deep space are always weak. To catch these waves, radio telescopes usually have huge antennas. The sizes of most antennas in use today are around 50 to 300 metres in diameter. The antenna of FAST in Guizhou, China, the latest and largest radio telescope in the world, is 500 metres in diameter, as large as the size of 30 football fields.

    To avoid interferences, and keep the telescopes sensitive, radio telescopes are built in places where there are no human radio waves or electronic signals. For example, FAST is 5 kilometres away from the closest village and 25 kilometres away from the nearest town.

    Radio telescopes create pictures of the sky, not in visible light, but in radio waves. This is extremely useful, because there are objects that can't be seen, objects that we wouldn't even know without radio telescopes.

"Learning a language is easy. Even a child can do it!"

Most adults who are learning a second language would disagree with the above sentences. For them, learning a language is a very difficult task. They need hundreds of hours to study and practise, and that will not guarantee success for every adult language learner.

Language learning is different from other kinds of learning. Some people who are very intelligent and successful in their fields find it difficult to succeed in language learning. However, some people who are successful language learners find it difficult to succeed in other fields.

Language teachers often offer advice to language learners: Read as much as you can in the new language; practise speaking the language every day; live with people who speak the language you want to learn; don't translate—try to think in the new language; learn as a child would learn—play with the language and so on.

But what does a successful language learner do? Language learning research shows that successful language learners are similar in many ways.

First of all, successful language learners are independent learners.

Secondly, successful language learning is active learning.

Finally, successful language learners are learners with a purpose.

What kind of language learner are you? If you are a successful language learner, you have probably been learning independently, actively, and purposefully.