To many people, art is a human expression of creativity. But in recent years, you may have read news about artificial intelligence (AI) creating its own art, such as painting or writing poems. Some people worry that AI might someday replace (替代) artists.

    But this worry seems to be unnecessary, at least for now. Many artists today are turning AI into a useful tool. Instead of replacing artists, AI is bringing artists more possibilities.

    A piece of music created by AI recently attracted attention. AI was used to create the music based on the protein (蛋白质) structure of COVID-19. The music lasted nearly two hours. The project was led by Markus Buehler, an American musician and MIT professor (教授) of engineering. He assigned (指定) a unique note (独特的音符) to each amino acid (氨基酸) is the protein. The AI then translated these notes into music.

    Listeners found the project "mind-blowing". "It allows me to see the virus in a new way," said one listener. This surprising combination (结合) between science and art could not be achieved without AI. As The Verge wrote, "AI helps artists play around in unpredictable ways, creating things beyond (超过) what they have ever thought was possible before."

    Apart from creating imaginative works, AI can also take care of repetitive (重复乏味的) tasks for artists. For example, in the comic and cartoon industries, there are now AI tools that can automatically (自动) color in black-and-white line drawings. Although the results can be unpredictable and require a little cleanup. it can give artists room to experiment (实验) by cutting down the time it takes to color each picture.

    As Peter Ward wrote for The Culture Trip. "Art of every kind has always been influenced by technological developments." AI can become a useful tool to bring change to the art world if it's welcomed and not unfairly feared.

    In many places the weather changes during the year. These changes are called seasons. In the north and south there are four seasons in a year. At the North and South Pole, there are only two seasons. In tropical (热带) places near the Earth's equator (赤道), there are two seasons: a 'wet' season and a 'dry' season. Each season brings changes. They are important for plants and animals that live in different parts of the world.

    Spring starts when the day and night are the same length. The weather gets warmer and sunnier. Trees and plants start to grow. Many animals have their babies in spring.

    Summer begins on the longest day of the year. In the north this is on June 21 or 22. Summer is usually the warmest and sunniest time of the year. Fruit grows faster on trees and plants. Young animals grow bigger and stronger.

    Autumn starts when the day and night are the same length again.

During autumn, the leaves change color and fall down from the trees. Some animals collect food before winter comes.

    Winter begins on the shortest day of the year. In the north this is on December 21 or 22. The weather is colder and in some places there is lots of snow. Plants and trees stop growing. Some animals, like bats and bears, find places to hide and sleep. This is called hibernation.

    Wind power is a very clean source of energy. This is how wind power works. Wind makes windmills spin (旋转). When the windmills spin, they make electricity. Then we can use the electricity.

    A lot of people think that wind power is new, but that's not true.

    For thousands of years, people have used wind to sail boats and move water. We still do those things today, but these days we mostly use wind power to make electricity.windmills

    Wind power is a very popular source of energy. Most people think that we should use it more and more. First of all, it's clean. Windmills don't pollute the environment at all. Second, we can use wind power forever. After all, we will always have wind. Also, wind power is cheap, and it's getting even cheaper.

    A lot of people don't understand wind power very well. They believe that there are problems with wind power, but many of those problems are not real. For example, some people say that windmills are dangerous for birds. They used to be true, but it isn't true anymore. Old windmills killed birds because they spun very fast. New windmills spin slowly, and they aren't dangerous for birds.

    However, there are real problems with windmills. One problem is that many people think windmills are very ugly. This is a problem for people, because windmills are often in very pretty areas. Also, wind doesn't blow all the time, so we can't use wind power all the time. Finally, windmills are noisy.

    Wind power is becoming more and more common. Right now, more than 80 countries use wind power. About 2.5 percent of the world's power comes from the wind. For some countries, that number is a lot higher. Wind power gives Denmark more than 25 percent of its electricity.

    How do people find their ways? At first, people did it by looking at the sun, the moon and stars, Later, we started to use the compass(指南针).Today, there are navigation satellite systems.

    A navigation satellite system uses groups of satellites, they send information to a receiver, such as your smart phone. Then they can find where you are.

    The earliest navigation system is the Global (全球的) Positioning System(GPS) of the United States, The US has put 24 satellites into space to make sure GPS can locate a person correctly and globally. Russia's GLONASS and European Union's Galileo can also work globally.

    The BeiDou Navigation Satellite System (BDS) is China's homegrown navigation system. It was set up in 2000. With it, China became the third country to build a navigation system after the US and Russia.

    BeiDou can find you wherever you are. It helps you go faster by finding shortcuts and using correct directions. When you are in trouble and call the police, they will know exactly where you are if you have a smart phone that uses BeiDou.

    Today, there are more than 20 BeiDou satellites above our heads. And the system is able to offer open services to the Asia— Pacific area.

    China plans to send more BeiDou 3 satellites into space. BeiDou—3's position accuracy(精确度) is less than five meters, By 2020, the BeiDou system will have 35 satellites and  begin serving Globally.

    What's a spacewalk? Any time an astronaut gets out of a spacecraft(航天器) while in space, it is called a spacewalk. Astronauts go on spacewalks for many reasons. For example, experiments can be placed on the outside of a spacecraft. This lets scientists learn how being in space affects(影响) different things. By going on spacewalks, astronauts can also fix things instead of bringing them back to the earth to fix.

    When astronauts go on spacewalks, they wear spacesuits to keep themselves safe. Inside spacesuits, astronauts have the oxygen(氧气) they need to breathe and the water they need to drink. To keep the astronauts and the spacecraft safe, the astronauts must leave and go back to the spacecraft through a special door. When on a spacewalk, astronauts use safety  tethers to stay close to their spacecraft. Tethers are like ropes, connect the spacewalkers with the spacecraft. They keep astronauts from floating(漂浮) away into space. Another way astronauts stay safe during spacewalks is by wearing a SAFER. SAFER is worn like a backpack. It helps an astronaut move around in space.

    How do astronauts train for spacewalks? One way is by going for a swim. Floating in space is a lot like floating in water. Astronauts practice spacewalks underwater in a huge special swimming pool. For every one hour they will spend on a spacewalk, astronauts need to train seven hours in the pool. Another way astronauts practice for a spacewalk is by using virtual reality(虚拟现实). It looks and feels just like a spacewalk.

    Today, only three countries have finished spacewalks independently. They are Russia, the United States and China. The first person to go on a spacewalk in the world was Alexei Leonov from Russia. Zhai Zhigang is the first Chinese astronaut to go on a spacewalk. The world record of spacewalks is held by Russian astronaut Anatoly Solovyev. He has been on 16 spacewalks and spent more than 82 hours outside in space.

    Some Fun and Interesting Facts

    Do you think what color oranges are? The common answer to this question is "Orange". However, the first oranges from Southeast Asia were actually green. Up to now, oranges in warmer areas like Vietnam and Thailand still stay green when they are fully grown.

    There was a man named John Chapman who planted thousands of apple trees. But the apples on those trees were much more bitter(哭的) than the ones you'd find in the supermarket today. John didn't expect has apples to be eaten whole, but rather made hard apple cider(苹果酒).

    Like most four-legged animals, cats have five toes on the front paws, but their back paws only have four toes. Scientists think they four-toe back paws might help them run faster. Do you know any other fun fact about cats?

    Walt Disney might have been the firs it gloves on his characters，as the star Mickey Mouse in 1929's The Opry House（《奥普里之屋》）.Besides being easier to interest, there's another reason why Disney did so "We didn't want him to have mouse hands because he was supposed to be more human." Disney once said.

    Most people agree that trees look nice, but not everyone knows that trees can also help cities save money. A few years ago, the US Forest Service studied trees in Chicago. They found that just one tree can save a city hundreds of dollars over its lifetime.

    Trees can save money by helping people save energy(能源). Trees stop the sun shining on buildings. They also block(挡住) the winter wind. That helps people use less energy to make their homes or offices warm or cool. Saving energy is saving money.

    Trees have another way to help a city save money. When it rains, there will be a lot of water in a city's sewers (下水道). Cities need lots of money to clean that water. But before the rainwater gets to the dirty sewers, trees can take some into themselves. With the help of trees, there is less water to clean.

    Some scientists say that animals in the ocean are increasingly threatened(威胁) by noise pollution caused by human beings. The noise that influences sea animals comes from a number of human activities. It is caused mainly by industrial underwater explosions(爆炸) , ocean drilling, and ship engines. Such noises are added to natural sounds. These sounds include the breaking of ice fields, underwater earthquakes, and sounds made by animals themselves.

    Decibels (分贝) measured in water are different from those measured on land. A noise of one hundred and twenty decibels on land causes pain to human ears. In water, a decibel level of one hundred and ninety five would have the same effect（效果）.

    Some scientists have proposed setting a noise limit （限度）of one hundred and twenty decibels in oceans. They have observed that noises at that level can frighten and confuse whales（鲸鱼）.

    A team of American and Canadian scientists discovered that louder noises can seriously injure some animals. The research team found that powerful underwater explosions were causing whales in the area to lose their hearing. This seriously affected the whales' ability to exchange information and find their way. Some of the whales even died. The explosions had caused their ears to bleed.

    Many researchers whose work depends on ocean sounds object to a limit of one hundred and twenty decibels. They say such a limit would mean an end to important industrial and scientific research. Scientists do not know how much and what kinds of noises are harmful to ocean animals. However, many scientists suspect that noise is a greater danger than they believed. It's time for them to take action to help ocean animals.

    Recently, a designer in Hong Kong has invented a special book that can transform (变形) into a piece of furniture. The special book is called Bookniture. It can be unfolded to become a chair or a small table. People can either carry it around for a portable (轻便的) chair or can store it in their homes to use as extra furniture.

    The book was designed by Mike Mak. He came up with the idea after never having enough seats for his friends in his home in Hong Kong.

    “I love having friends at my place, but I have never had enough seats for everyone—we would always end up with just sitting on the floor. 1 really want a seat that doesn't take up any floor space when I don't need it. One day, the empty space on my bookcase drew my attention.  Then came the new idea—Bookniture, furniture hidden in a book,” said the 30-year-old designer.

    Made from fully-recyclable kraft paper (牛皮纸) , the book measures 33 cm by 18 cm. It expands (扩大) to 14 times bigger once it's opened, and can support up 10 1,000 kg of weight.  It comes in two colors, brown and black, and can be bought for between￡55 and ￡57.

    Wearing a white blouse, Ai-Da studies her subject and begins to draw. She looks like any artist at work. However, the "beep ... beep ... beep" noise from her arm gives her away. Ai-Da is, in fact, a robot.

    Ai-Da has been described as the world's "first Al (人工智能) robot artist". She takes her name from Ada Lovelace, the world's first female computer programmer. Scientists at Oxford University developed Al systems (系统) for Ai-Da. The robot has cameras in her eyeballs. After she has studied a subject, she will use her left arm to draw. Now, Ai-Da can only use a pencil for sketches (素描).The plan is for her to paint.

    Ai-Da is not the first Al system to produce artworks. Since 2006, scientists have been developing software (软件) to turn photos into drawings. Last year, an artwork created using Al was sold in New York for$432,500. However, Ai-Da's human-like appearance." brings something new to the field.

    In June, Ai-Da opened her first exhibition at Oxford. Then were about 30 drawings by the robot. Ai-Da, standing next to her artworks, attracted (吸引) many visitors.

    Ai-Da's inventor, Aidan Meller, talked about the importance of the robot. "Ai-Da bring a new voice to the art world," she said "Al is going to be the big thing of the 2020s. That influences us greatly." Meller hopes the exhibition was just the start and that more will follow to show how AI is influencing human life.

    The longest river in the world is the Nile. It is 4,160 miles long. But the Nile is not the mightiest (浩荡的) river. The Amazon is. The Amazon is also the second longest river in the world. It is 3,900 miles long. How long is that? It is longer than a road going from New York City to San Francisco.

    The Amazon is the mightiest for this reason. It has the greatest amount of water. More water runs out to sea than from the Nile. Mississippi, and Yangtze rivers combined. That's a lot of fresh water! The force of its current (水流) is great too. The current can be seen 200 miles out in the sea. There's a story to show the Amazon's amazing current. A ship sailed (航行) far away from Brazil. It ran out of drinking water. Another ship passed by. The first ship asked for water. Someone on the second ship said. "Just put your buckets (桶) into the sea."

    Here are a few more facts. At its mouth, the Amazon is 90 miles wide. Even up the river, you can't see the opposite bank. The river is also very deep(from 22 to 76 meters). During rainy season, the river rises about 16 meters more. Big ocean ships can sail about 1,800 miles upstream (向上游). Smaller ships can sail 1,000 miles farther.

    What's the most bloodthirsty fish in the world? No. It's not the shark It's the Amazon's piranha.It is only about 10 cm to 20 cm long. It has sharp teeth. Thousands travel in a group. No animal can swim across the river. A 1,000-pound horse would be just bones (骨头) in three minutes. Are you planning a trip to the Amazon? Here's a piece of advice. Leave your swimsuit at home!

Whether from news reports or social media articles, you may know that 5G is coming.

5G is the 5th generation network. It is a new network (网络) after 1G, 2G, 3G and 4G and it can connect everyone and everything together. 5G networks will cover/many cities in China soon. 5G means super-fast data (数据) speed, One can download a two-hour movie for fewer than 10 seconds, and it is making our hives more and more convenient.

    5G will make self-driving cars possible. For safety, self-driving cars need super-fast data transmission (传输) to communicate with their nearby environment. 5G is just what makes self-driving cars achieve this, even airplanes will become "smart" in the near future. Passengers will be able to use 5G networks in the air to connect to the Internet or place orders for food and drinks.

    5G will be a big help for students who take online classes. Many people live in poor areas in the world where there are no schools. But with 5G, this will change. Students all over the world will be able to see places like the Great Wall without leaving their rooms.

    It will be also easier for doctors to treat patients remotely by 5G. It means caring for patients from far away.

    The fats listed above are only a part of what 5G will make possible and popular. Just as in the early days of the Internet in the 1990s, few could see how it could change or lie and the world. The same will surely be true of 5G. With 5G, many things do not seem like dreams anymore. Now let's get ready to say goodbye to 4G and welcome the coming of 5G.

    Part of Earth's beauty comes from its oceans. Ocean scientists study the chemical make-up of the ocean, weather patterns, the geography of the ocean floor, and many other areas. Their work is exciting, although sometimes dangerous. Using technology to do certain tasks helps. For example, robotic arms are used for very dangerous tasks.

    One basic part of ocean study is understanding waves and how they work. Wind is the great maker of waves. The waves we know are mostly produced by winds blowing over the sea. They are directly connected with the wind speed and the time that wind lasts.

    Sometimes ocean life can be seen in the wave. Living things seem to be staying within the wave, moving slowly inside it as if they were weightless. Besides the beauty of waves, scientists are interested in their technical ways. The diagram of waves shows how scientists examine waves. Waves are measured (测量) from the top (crest) to the bottom (trough). This allows scientists to find out the height of a wave. They also measure waves from crest to crest to determine (测定) the length of a wave.

    During serious storms, huge waves migh cut a sea ship apart. Ships are at great risk of winding up as broken pieces after being hit by the force of a huge wave. By understanding the ocean, scientists can prevent this breakup of ships by predicting when the water will be too dangerous for people and their ships. The study of waves and the ocean also allows scientists to make sure how certain beaches were formed. By studying the oceans, a great deal can be learned about the surface we live on.

    Like you, plants need good things like food, water, and minerals in order to grow. Usually they get these important nutrients(营养) from the rich soil(土壤) in which they're planted. But there's another way to grow plants that doesn't use soil. It's called hydrogenic gardening.

    "Hydrogenic" means "working with water." In a hydrogenic garden, plants grow with their roots in water, not in dirt. The water is filled with special food for the plants that gardeners have carefully measured and prepared.

    Hydrogenic plants grow quickly. In ordinary gardens, plants need time and energy to grow long roots that search the soil for food and water. In a hydrogenic garden, plants can use their energy to grow tall instead. And because there is no soil, there are no weeds and few insect pests(害虫). Gardeners don't need to spray(喷洒) plants with dangerous chemicals. Both the plants and the environment stay healthy. 

    Scientists hope that, one day, hydrogenic gardens may be able to help hungry people all over the world grow enough food-even in countries that have bad soil, or weather that is too hot, too cold, or too dry. And astronauts hope to take hydrogenic gardens with them to the spaceship they fly to Mars, so that they will always have fresh vegetables, and the fun of growing a garden without dirt. 

    We know people can be nice, but what about animals?

    Scientists say that some animals are capable(有能力的)of being nice. Animals that live in groups-like foxes, chimpanzees(大猩猩), and elephants-follow rules. They have to follow rules to get along and to survive(生存). However, animals can act nicely, even when they don't have to. Here are some surprising stories about animal behavior.

    Most people usually walk away when someone is unkind to them. Marc Bekoff, a researcher at the University of Colorado, saw a female(母的)red fox do just that. The female fox was unhappy because a male(公的)fox played roughly(粗鲁地)with her. When she walked away, the male fox showed her that he wanted to play nicely. He lowered his head and rolled on his back. The female fox gave him another chance, and this time, he played more gently.

    Geza Teleki is a scientist who studies chimpanzees in Tanzania. One day, Teleki hiked far away from his campsite. He didn't have any food. Teleki wanted some fruit from a tree, but the tree was too tall. A young chimpanzee watched him curiously as he tried to get something to eat. The chimpanzee climbed the tree, picked the fruit, and gave it to him!

    An elephant in Kenya hurt his trunk(象鼻子). He needed help because he couldn't put food into his mouth. Researcher Kayhan Ostovar watched silently. He saw the hurt elephant show his sore trunk to a healthy elephant. The healthy elephant didn't need any more information. He took a bush and put it carefully into his new friend's mouth.

    Hippos(河马)and crocodiles are usually good friends. They hang out together in rivers. But Karen Paolillo, a wildlife expert in Zimbabwe, saw something surprising. One day, a crocodile tried to eat a monkey that was next to a river. A hippo ran quickly to the crocodile and chased it away. Why did the hippo attack(攻击)the crocodile? Paolillo says hippos sometimes protect other animals from crocodiles.