My color television has given me nothing but a headache. I was able to buy it a little over a year ago because I had my relatives give me money for my birthday instead of a lot of clothes that wouldn't fit. I let a salesclerk fool me into buying a discontinued model. I realized this a day late, when I saw newspaper advertisements for the set at seventy-five dollars less than I had paid. The set worked so beautifully when I first got it home that I would keep it on until stations signed off for the night. Fortunately, I didn't got any channels showing all-night movies or I would never have gotten to bed.

    Then I started developing a problem with the set that involved static (静电) noise. For some reason, when certain shows switched into a commercial, a loud noise would sound for a few seconds. Gradually, this noise began to appear during a show, and to get rid of it, I had to change to another channel and then change it back. Sometimes this technique would not work, and I had to pick up the set and shake it to remove the sound. I actually began to build up my arm muscles(肌肉) shaking my set.

    When neither of these methods removed the static noise, I would sit helplessly and wait for the noise to go away. At last I ended up hitting the set with my fist, and it stopped working altogether .My trip to the repair shop cost me $62, and the set is working well now, but I keep expecting more trouble.

Yesterday and Today

    Life in the twenty-first century will be different from life today. Between then and now many changes will take place, but what will the changesbe?

    The population is growing fast. There will be many people in world and most of them will live longer than people live now.

    Computers will be much smaller and more useful, and there will be at least one in every home. And computer studies will be one of the important subjects in schools then.

    People will work fewer hours than they do now and they will have more free time for sports, watching TV and travel. Traveling will be much cheaper and easier. And many more people will go to other countries for holidays.

    There will be changes in our food, too. More land will be used for building new towns and houses for all the people. Then there will be less room for cows and sheep, so meat will be more expensive. Maybe no one will eat it every day. Instead they will eat more fruit and vegetable. Maybe people will be healthier.

    Work in the future will be different, too. Dangerous and hard work will be done by robots. Because of this, many people will not have enough work to do. This will be a problem.

    Last year DeepMind's AlphaGo programme took on and beat two of the world's best players of the Chinese game of Go（围棋）-an unbelievable achievement seen as a milestone in the development of artificial intelligence (A). That programme was trained by first giving it vast amounts of data from amateur and professional games.

    The new AlphaGo Zero began with a blank board and nothing but the rules of Go and set about playing against itself. Within three days it was so advanced that it took on the previous version, which had taken months to develop, and defeated it by a hundred games to zero.

    DeepMind says that creating knowledge from first principles without learning from human expertise（专门技能）is an important step in developing artificial intelligence. The company's founder Demis Hassabis said this breakthrough could help in real world problems such as designing new drugs or discovering new materials.

    In 1997, Garry Kasparov was defeated by Deep Blue, a computer program written by IBM, running on a supercomputer. This was the first time that a ruling world chess champion was defeated by a computer program in tournament conditions. Superficially, AlphaGo's win against Lee Sedol can be compared to Deep Blue's win against Gary Kasparov, which happened almost 20 years ago. So: what's the big deal? We have to understand the differences between chess and Go.

    In chess, each player begins with 16 pieces of six different types. Each piece of type moves differently. The goal of the game is to seize the other player's king. Go starts with an empty board. The goal of the game is to gain as much territory（领地）as possible.

    Although the rules of Go might appear simpler than those of chess, the complexity of Go is higher. Also, games usually last longer for lots of moves. A typical game in Go might last for 150 moves vs.80 in chess.

    For students at the Farm School in Hamilton, Virginia, the classroom is outside every day. Jaclyn Jenkins is the founder of the school. “The No. 1 question we get immediately from parents is 'What happens if it rains?' And we say, 'Bring an extra set of clothes!'” Jenkins adds, “We still educate them. Their brains are working when they're moving. So, our goal is to always be outside.” The Farm School is a preschool, a place for 3- and 4-year-olds to learn and play.

    Alison Huff has taught at other schools. She says the Farm School gives its students more of a hands-on learning experience. For example, children use pumpkins to learn about colors and counting. They learn about measurement by planting seeds 30 centimeters apart. Huff adds, “We can use everything a regular preschool uses, but out in the garden.” In addition to planting vegetables and fruits, children help prepare food and clean up afterwards. The school teaches the children to cook using the food they have grown. “They can see the benefits of what they have in the garden and taste it then instead of going to the grocery store and buying it,” says Huff.

    The preschoolers also learn words in languages other than English. Huff speaks in both English and Spanish. Her assistant speaks French and Arabic. A 3-year-old in her class speaks four different languages.

    Farm animals are also an important part of the education program. Jenkins says the children learn about a different animal every month. Two months ago, she says, that animal was a cow. “We do actually have a cow that we bring to the school. They get to see what the cow is like, an learn what cows eat. They use little gloves and pretend to actually milk a cow. They make butter and yogurt.” The children spent another month with a large bird — a turkey.

    The idea for a school like this started after Jenkins and her husband bought a farm in Hamilton, with a late 18th-century house. They called it “One Day Farm” because years earlier they had hoped that “one day” they would have a farm. “That's when it started, the spark of a farm school,” said Jenkins.

    A year after graduation, I was offered a position teaching a writing class. Teaching was a profession I had never seriously considered, though several of my stories had been published. I accepted the job without hesitation, as it would allow me to wear a tie and go by the name of Mr. Davis. My father went by the same name, and I liked to imagine people getting the two of us confused. "Wait a minute," someone might say, "are you talking about Mr. Davis the retired man, or Mr. Davis the respectable scholar?"

    The position was offered at the last minute, and I was given two weeks to prepare, a period I spent searching for briefcase and standing before my full-length mirror, repeating the words, "Hello, class. I'm Mr. Davis." Sometimes I would give myself an aggressive voice. Sometimes I would sound experienced. But when the day eventually came, my nerves kicked in and the true Mr. Davis was there. I sounded not like a thoughtful professor, but rather a 12-year-old boy.

    I arrived in the classroom with paper cards designed in the shape of maple leaves. I had cut them myself out of orange construction paper. I saw nine students along a long table. I handed out the cards, and the students wrote down their names and fastened them to their breast pockets as I required.

    "All right then,'' I said." Okay, here we go." Then I opened my briefcase and realized that I had never thought beyond this moment. I had been thinking that the students would be the first to talk, offering their thoughts and opinions on the events of the day. I had imagined that I would sit at the edge of the desk, overlooking a forest of hands. Every student would shout. "Calm down, you'll all get your turn. One at a time, one at a time!"

    A terrible silence ruled the room, and seeing no other opinions, I asked the students to pull out their notebooks and write a brief essay related to the theme of deep disappointment.

    In the short time Steve and Zach had been inside their tent packing their tools, wind-blown flame had skipped from the top of one tree to another. The long dry summer had turned the forest into a tinderbox.

    "Let's go! We can make it back to the river we crossed today!" Steve kept Brady on the lead and their heads down against the fire-wind. But Brady barked a sharp warning. Ahead of them lay a thick curtain of smoke across the track. They would never make it through that. The dog was pulling at his lead trying to draw them away from the smoke, and yet Steve was uneasy. It seemed to him that they were moving away from the river.

    Suddenly, Zach cried. "Zach!" Steve shouted. "Are you OK? Where are you?" Then Brady pulled Steve down a sharp slope(坡). At its base, Zach was rubbing his ankle.

    As Steve helped his friend to his feet, Brady lifted his head and snuffed(嗅) the smoke-laden wind. Next moment, the dog bounded away and disappeared. The boys shouted for him, but he didn't come back. Steve couldn't blame Brady for panicking. He himself wanted to run even though he didn't have a clue which way.

    Steve and Zach hadn't gone far when there was a familiar bark, and Brady came bounding, stopped directly in front of Steve and hit him with his head, pushing him back toward the slope they'd just climbed. But Steve didn't get it. Then Brady grabbed the boy's jeans and started pulling. The message was clear, but Steve hesitated. Of course he remembered Brady saving his uncle's life when the dog was much younger. Was he still sharp enough to get them through this?

    Nearby, a pine went up in a whoosh of smoke. Brady pulled again, urgently. "OK, big guy," Steve gritted(咬紧牙关). Brady led them back down the slope and into the trees. Not far from them fire was touching underbrush. Several times the big dog stopped. Often he changed directions. Steve was so tired that he just wanted to rest, but Brady wouldn't have it. The dog bullied both boys to go on. How long they'd walked Steve had no idea. He was almost numb when he heard it—the wonderful sound of rushing water!