Water has always been necessary for our health. Then what kind of water do you drink, tap water or bottled water? Do you get a healthier, safer and more refreshing(提神的) drink when you buy bottled water off the shelf? My answer is "no", and doing so hurts the environment and your wallet.

    First of all, there are no studies showing that bottled water is better for you, and in fact, it may be less safe than tap water. A study of over l, 000 people in Belfast found that they couldn't tell the differences between tap water and bottled water when asked which was purer, more pleasant, natural and refreshing. Bottled water can come from springs(泉水) or from the mountains. It can also be treated, for example, to have iron(铁) removed. It is reported that there is around 82.8g of CO₂ for a half-liter(半公升) bottle. This will be harmful to people's health when everyone's drinking it. However, bottled water is popular with many people. Its success is from excellent marketing and our laziness in filling reusable bottles with tap water.

    Secondly, bottled water can cost between 500 to 1, 000 times more than dap water. In 2015, the UK drank 2.4 billion liters o of bottled water, and by 2016 this had risen to 2.6 billion liters. Yet, you get this from the tap, for free.

    Besides, recycling is improving, but in America, it is said that only a quarter of bottles can be used again. So is it really so much better that it is worth both paying for and harming the earth? Or should you stop buying it?

    As a general rude, I believe that most of us should enjoy more tap water, and stop using so many bottles.

    Why don't birds get lost on their long flights (飞行) from one place to another? Scientists have studied this puzzle for a long time. Now they're starting to fill in the blanks(空白).

    Not long ago, experiments showed that birds use the sun to guide them during daylight hours. How do birds fly at night? Tests with artificial stars, which are made by people, have proved that certain night-flying birds are able to follow the stars in their long-distance flights.

    They found a bird that spent its lifetime in a cage and never flew under a natural sky. But it was born with the ability to use the stars to look for the direction. This bird's cage was placed under the sky filled with artificial stars. Any change in the position of the artificial stars caused a change in the direction of the bird's flight. From the experiment, they found that the bird tried to fly in the same direction as those artificial stars moving under the natural sky.

    But the stars are of course birds' main ways of navigation (航行), when the stars are hidden by clouds, they can still find their way by such landmarks (路标) as river courses, mountain ranges (山脉), coast lines and so on. Because of this ability, people use the dove (鸽子) to send messages in some fields. For example, the doves were used to send messages in both World War I and World War II. During that time, thousands of doves were used to carry important messages in order to save the lives of many thousands of people. So it is also the symbol of peace.

    But when it's too dark to see these things, the doves are not able to find their way. They only circle helplessly and get lost.

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    The human brain is divided into two sides, or hemispheres, called the right brain and the left brain. The two hemispheres work together, but each one specializes in certain ways of thinking.

    Each side has its own way of using information to help us think, understand, and process informa—tion.The left side of the brain controls language. It is more verbal and logical. It names things and puts them into groups. It uses rules and likes ideas to be clear, logical, and orderly. It is best at speech, reading, writing, and math. You use this side of the brain when you memorize spelling and grammar rules or when you do a math problem.

    The right side of the brain is more visual and creative. It specializes in using information it receives from the senses of sight, sound, smell, touch, and taste. This side of the brain likes to dream and experiment. It controls your appreciation of music, color, and art. You use this side when you draw a picture or listen to music.Although we all use both sides of our brains, one side is usually stronger or dominant. Some people are more “left—brained,” and others are more “right—brained”. Our dominant side influ—ences the kinds of jobs and hobbies we have. Politicians, artists, architects, and musicians depend on their right brains. Accountants, engineers, doctors, and lawyers usually rely on their left brains.

    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.

    Bioplastic(生物塑料) is a kind of plastic, but it is not the same as normal plastic. Normal plastic is made from chemical materials and takes a very long time to degrade(降解). But bioplastic is good for the environment. It is made by using bacteria(细菌) to process(加工) natural sources like vegetable oils, corn or sugar. It can degrade more easily.

    But there is a problem with bioplastic. The "food" that bacteria eat is what we eat. This means that bacteria are competing against humans for the same resources.

    Now scientists have found a new way to make bioplastic——using two kinds of bacteria and sunlight, according to Newsweek.

    One of the bacteria can use sunlight to produce sugar. The other kind lives in the salty waters of Bolivia. It eats the sugar that the first bacteria produce and then it can produce polymers(聚合物). Polymers are used to create bioplastics. The way the bacteria store polymers is similar as humans store fats.

    The new way to produce bioplastic has many advantages. It is 20 times faster than the normal way we produce bioplastic. Moreover, using these two bacteria saves resources.

    Firstly, producing a lot of bioplastic requires corn and sugar, which are used to feed normal bacteria. And growing corn and sugar needs farmland. But these two bacteria can just use sunlight. The land that is saved can be used to grow food for humans. Besides, this system doesn't need rich land or clean water at all, scientists said to Newsweek.

    The next problem scientists face is that they want to put their lab research into real-world practice. By doing this, bioplastic made with these two bacteria can be widely produced in the future.

    Welcome to the 26^th century! Cyborg technology is a way of life. People with human brains and artificial (人造的) bodies are everywhere.

    This is the future world shown in the film Alita: Battle Angel.US director James Cameron made the film. The movie came out in the Chinese mainland theaters on Feb 22.

    The story is based on Japanese manga artist Yukito Kishiro's popular manga series of the same name. The main character, a cyborg, is a girl named Alita.

    One day, she wakes up in wreckage and finds that she has lost her memory. Luckily, a doctor saves her. As she starts her new life, Alita finds she has superhuman abilities. She decides to find the truth behind her origin. She started a journey that leads her through a dark world.

    In Cameron's own words, the movie is "not like any of the films that I've done before". Its visual effects are especially impressive. The film's actors used the latest motion-capture (动作捕捉) technology. They wore special suits that record their movements. Later, motion-capture editors use these movements to make special effects. Rosa Salaza plays Alita. She wore a suit with more than 7, 000 pieces and layers. It can capture human movement. The model that was used for her face was changed nearly 5, 000 times to make it more lifelike.