Florida teen band The Garbage-Men is performing on the stage. The band has five members. They are Jack Berry, Ollie Gray, Harrison Paparatto, Austin Siegel and Evan Tucker. The five teens are making music from waste. The Garbage-Men band's instruments are made from recycled things. The guitars are boxes. A horn(号) is made from pipes. The keyboard is formed from old bottles.

    The band started about two years ago. Jack Berry who was in eighth grade at the time decided to make a playable, home-made guitar. After some trial-and-error(反复试验),                he ended up building it from a cereal box,  a yardstick and toothpicks. After Jack showed his creation to his friend Ollie Gray, Ollie had the idea to form a band using other home-made instruments as a way to improve recycling. “We want to show people there is more to recycling than throwing things away in the bin.” Jack, 16, told TFK. “You can actually reuse materials.”

Last year, the Garbage-Men played at local events, including festivals, farmer's markets. Typically， the teens set up on the street and performed popular songs from the 1960s， including classic Beatles and crowd favorite “Wipe Out”. They talked about recycling and offered tips for how to improve the environment. While they were performing, Jack's little brother Trent, 11, gave out leaflets about recycling and helped sell the band's CDs and other musical products.

The band donated the money from sales to charity. They have raised more than $2,500 for Heifer International. The organization gives farm animals, seeds and agricultural training to people in poor countries to help end poverty and hunger. “It's a good, sustainable-development (持续发展的)charity,” Jack says, “By donating one animal, you help the whole community.”

The band, all tenth graders, tries to play a show every week. They've also played on a Florida radio station. The teens hope to take their shows on the road by touring in other states. “Music is a really good way to get a good message across to people because it's really close.” Jack says. Their instruments may be rubbish, but their message isn't.

    The polar bear is a very big white bear. We call it the polar bear because it lives in the Arctic Circle（北极圈） near the North Pole.

    The polar bear lives in snow and ice. At the North Pole there is only snow, ice and water. There is not any land. The polar bear has a very warm coat because the weather is cold in Arctic Circle. You can't find the polar bear easily in the snow because its coat is white.

    A grown-up polar bear is usually about three meters long and weights about 450 kilos. It can stand up on its back legs because it has very wide feet. It can use its front legs like arms. The polar bear can swim very well. It catches fish and sea animals for food. It goes into the sea when it is afraid. People kill the polar bear for its beautiful white coat. The governments of Canada and United States call on that people should stop killing polar bears. They don't want these beautiful animals to die out.

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     Kumar and his two friends built a robot and named it Athena. They would go for Battle of the Bots--the city's biggest robot competition, and it would start in two days. The winning team would get $5,000.

     "How are we going to beat (打败) the Cougars?" asked Alex. The Cougars was the team that won the last two years' competitions.

    Kumar said, "The Cougars always build a big and strong (强壮的) robot. But usually their robot isn't very fast."

    "Our robot is fast," Alyssa said.

    "Yes!" Kumar said. "Don't worry. I have a plan for how to do it." Kumar told the group his plan and they began to work.

    Two days later, the competition began. Kumar said to his friends, "I' m sure the plan will work and Athena will win. Just wait and see."

    Athena won all of her first battles (较量). The Cougars' big, strong robot, The Avenger, did well, too. By the end of the day, The Avenger and Athena were the only two robots left in the competition.

    Soon the battle between Athena and the Avenger began. The Avenger lunged (猛扑) for Athena, but the small robot was too quick for him. Athena went behind The Avenger and, before the larger robot had time to turn, Athena hit (攻击) him from behind. The Avenger fell" down and couldn't move.

    The three friends all jumped up excitedly. "Now it's time for the real question," said Alex“      ”

    You and I can tell one face from another easily, but can computers do the same with few mistakes? At an earlier time, many thought it was impossible, but progress in facial recognition(识别)software has made it come true. Technology is quickly catching up with the human ability to read faces.

    Some facial recognition systems use a digital picture and measure(测量) different points on the face. Measurements include the distance between the eyes, the width of the nose, the length of the jaw(下巴) line and more. A detailed map, or faceprint, of the face is developed, stored and later used as a basis for comparison and matching.

    Some government agencies, airports and banks use facial recognition technology for safety purposes. Apple and Facebook use it to provide their users with added convenience. For example, Apple's new iPhone is expected to use it to unlock the home screen. Other companies use it to help them in better recognizing their customers' needs. For example, some stores are checking into the use of the technology to catch sight of return customers. Then they can offer special deals, based on the customers' buying habits.

    In America, facial recognition is used by universities to check students' attendance. This year Welsh police used it to catch a terrorist outside a football game. In China it checks on the identities of ride-hailing drivers, permits tourists to enter some places of interest quickly and lets people pay for things with a smile.

    While some systems are used with the knowledge of the persons, others aren't, and that raises worries. For many people, however, convenience outbalances the worries, in other words, meaning that facial recognition technology is likely here to stay.

    Have you noticed the waste bins(垃圾桶) in different colors on the street? Do you often put all the waste in the same bin? It's reported by Changchun Daily that people must do waste sorting(分类)in most places in Changchun at the end of 2019. Waste sorting is a wonderful way to make good use of energy and protect the environment. But do you know how to sort the waste?

    Usually, people should sort their waste into four groups: wet, recyclable, harmful and dry. Different kinds of waste should go into different bins. Wet waste means the things you don't want but pigs can eat, mostly coming from your kitchen. Things that can be used again, such as paper, metal and glass, are recyclable waste. Harmful waste might be dangerous or cause serious pollution, like medicine and batteries(电池). And any waste that's not wet, recyclable or harmful will go into the dry waste bin.

    Different countries are trying different methods to sort the waste. A university in England has invented a smart bin. When people drop their waste into the bin. It can tell what kind of waste it it and sort it correctly. The bin can also compress the waste to make it smaller in size and take up less space. In South Korea, people have to separate their food waste from other kinds of waste and pay for it. The more food waste they throw away, the more they pay. Japan has the strictest rules for waste sorting in the world. For example, plastic bottles and their caps should go into different bins.