In 1826, a Frenchman named Niepce needed pictures for his business .But he was not a good artist .So he invented a very simple camera. He put it in a window of his house and took a picture of his garden .That was the first photo.

    The next important date in the history of photography was in 1837. That year, Daguerre, another Frenchman, took a picture of his reading room .He used a new kind of camera in a different way. In his picture you could see everything very clearly, even the smallest thing. This kind of photo was called a Daguerreotype.

    Soon, other people began to use Daguerre's way. Travelers brought back wonderful photos from all around the world .people took picture of famous buildings, cities and mountains.

    In about 1840, photography was improved .Then photographers could take pictures of people and moving things .That was not simple .The photographers had to carry a lot of films and other machines. But this did not stop them, for example, some in the United States worked so hard. Mathew Brady was a famous American photographer. He took many pictures of great people .The pictures were unusual because they were very lifelike.

    Photographers also became one kind of art by the end of the 19th century. Some photos were not just copies of the real world .They showed feelings like other kinds of art.

    The expression "lanshouxianggu" has been quite popular on Chinese social networking sites. You may have used it many times when chatting online. However, did you know that the "blue thin mushroom" was not just magic of Photoshop and was really there in nature?

    Well, let' s meet Entoloma hochstetteri (霍氏粉褶菌).This is a kind of naturally-blue fungus(真菌) The plant looks very small. Its sten' s diameter(梗的直径) measures only about 5 millimeters. Entoloma hochstetteri can be found widely in New Zealand, especially on the west coast. The Maori name for it is "werewere-kokako." It seems New zealand is very proud of producing this unusual species-the country prints the blue mushroom on its $50 notes.

    Athough the species is very unusual, little is known about it. Silas villas-boas is a scientist at the University of Auckland. He said he was very disappointed that nobody had ever tried to test the blue mushroom in the lab, "You can even count the number of scientific articles on it on one hand, he said. The scientist decided to be the first to study the plant. A group of researchers have been helping him with the study.

    In an early test, the researchers found alkaloids(生物碱) and Omega-3 fatty acids(w-3脂肪酸)in the blue mushroom. While the acids are helpful to health, alkaloids soetimes influence how the brain works. However, Villas-Boas said the substance was very common in plants. So far, the researchers have not found any toxins(毒素) in Entoloma hochstetteri, but they are not yet sure if it can be eaten. Villas-Boas said more testing would be required.

    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.

    On July 1, 2019, Shanghai began the waste sorting programme. There are four kinds of waste: wet waste, dry waste, dangerous waste and recyclable waste. Under the new rules, people must put their waste in the right place. Or they will be fined more than 50 yuan and less than 200 yuan.

    Sorting waste is very important. By doing so, we can take out non-degradable(不可降解的)waste and save resources(资源)In return, we can get a better environment.  ▲   Luckily. Internet companies like Wechat, Baidu and Alipay made apps to help.

    How do we use the apps? Just open one waste-sorting app and write down the keyword. Then the app will tell us the answer and why, Alipay says its waste-sorting app got one million users in just three days and the number is still growing. They are working on the app and people may use it by taking photos in the future.

    The waste-sorting programme is the talk of the whole country now. And another 21. 3 billion yuan will be used on the programme in 46 cities by the end of 2020.

The Arctic Region（北极地区）is one of the coldest place in the world. It is cold all the year round. Spring comes from May to June. The ice and1 begin to melt. The plants begin to grow and the animals look for2 . The summer comes from July to August. The temperature in summer can get only -8℃. It should be the warmest3 here. Autumn comes from September to October and it lasts4 .5 comes quickly from November to April next year. Winter is the6 and coldest season of a year. And the Arctic Region is filled with ice and snow everywhere. At this time there is no7 . So it looks like night in winter.

Are there any people living in such a8 place? Yes, they are Eskimos. It is9 for them to live there, but they live happily with a long10 .