文章结构题 知识点题库

    When was the last time you did something really fun with one of your parents—just the two of you?

    Parents who take their young children to music，swimming and art classes often stop arranging such activities once their kids are older and in school all day.But it doesn't have to be that way.Doing something enjoyable with your kids just might make you look at each other in a whole new way，especially if you do it through a class or an event.When parent and child become students together，it puts them on the same level，at least for a while.

“I really like parents to come to class with their kids—they start sharing things and talking about what they’re doing and what they like，” said art teacher Pyper Dixon.

    However，finding something new in common is a big  choice for them，especially when kids get involved in sports and other after­school activities.But it's possible to learn a new skill or hobby together.

    That's certainly true of Lauren,11，from Silver Spring，who is in Dixon's class with her father，Dennis.“I was just going to drop her off，” Dennis said，“but Dixon persuaded me to stay.”

    Now Lauren gets to nag her father about doing his art homework.“He always leaves it to the last minute，” she said.“But then he'll turn around to do amazing drawings，”  she added.“We have different styles of drawing，so it's interesting  to talk it over with him.”

    Without the Saturday morning art class，Dennis said，he  would be reading the paper，and Lauren would be on her own in her room or on the computer.But they talk more now.“I can't think of an experience where you communicate with your kid so closely，” he said.

    Do you want a bit of an adventure? Would you like to discover all the corners of the UK, or travel abroad? Maybe you have never tried the motorhome lifestyle before. Well, read this article and you will know why a motorhome is a good choice.

    Nothing is better than a motorhome. It has so many uses that it is considered the most versatile vehicle and it is also very comfortable. If you are thinking about hiring a motorhome this summer, then the best choice is to book it early, especially if you are considering the school holidays. The motorhome hire service is very seasonal and motorhome hire companies will never have extra vehicles available in the summer months.

    There are a lot of companies throughout the UK, and some of the big ones have motorhomes spread all over the country. At present, the largest network for motorhome hire is provided by Motorhome which is based in Cambridge. If you are in the UK, you may phone 0800612-8719 for details of its motorhome hire information. Motorhome has a network of over 500 vehicles all over England, Scotland and Wales.

    Most people wishing to hire a motorhome are families that are looking for an alternative to a European package holiday, especially as flying now has become more expensive, and is considered to be environmentally unfriendly. There is no doubt that the idea of no-fly holidays is going to become more popular as fewer people think it is safe to fly. This explains why more and more people are choosing to hire a motorhome for their holidays.

    As I enter my 40s, I've noticed many of my parents' generation think social networking is something they are simply unable to understand. They fear that, should they try, they will somehow get it wrong; they will say the wrong thing, do the wrong thing or behave in a way that causes embarrassment(尴尬). But here's the first secret of social media: Everyone feels this way.

    I recently met a young actor who was complaining that her work demands that she join Microblog, but she always feels like she doesn't have anything smart to say. It's the same resistance (抵制)I hear from the older generation, who, however, have somehow believed that age is the barrier(障碍), rather than the differences of personal taste.

    Here's the second secret of social media: everybody uses it for more or less the same reasons. Older generations often sign up to stay in touch with children and relatives. We talk about this kind of communication like it's some old-fashioned activity, but it is exactly why younger people use social media. The truth is that most people use social media to gently keep an eye on one another, to see how those they care about are doing without needing to ring them up on the phone every night.

    And this is the last secret of social media: everyone gets to use them in their own way. Newcomers—younger and older—who worry about “getting it right” are thinking that there's a right way to get them. But actually there isn't. Personally, I talk a lot on Microblog. And some people post nothing and they use social media every day as readers. Social media companies would rather see people decorating their networks with pictures and posts, but there's no rule against being a fly on the wall. It's also a fine way to get involved.

    We're quick to forget that the web wasn't invented by 13-year-olds; it was created by today's seniors. I'd never try forcing those with no interest in social networks to use Microblog. But don't let the talk of age divides put you off. There's nothing to stop the older generation from joining in the network their own generation created.

    The U. S. Postal Service (USPS) is losing billions of dollars a year. The government company that delivers "small mail" is losing out to email and other types of electronic communication. First-class mail amount fell from a high point of 104 million pieces in 2000 to just 64 million pieces by 2014.

    Congress permits the 600.000-empIoyee USPS to hold a monopoly (垄断) over first-class and standard mail. The company pays no federal, state or local taxes; pays no vehicle fees; and is free from many regulations on other businesses. Despite these advantages, the USPS has lost $52 billion since 2007, and will continue losing money without major reforms.

    The problem is that Congress is preventing the USPS from reducing costs as its sales decline, and is blocking efforts to end Saturday service and close unneeded post office locations. USPS also has a costly union-dominated workforce that slows the introduction of new ideas or methods down. USPS workers earn significantly higher payment than comparable private-sector workers. The answer is to privatize the USPS and open postal markets to competition. With the rise of the Internet, the argument that mail is a natural monopoly that needs government protection is weaker than ever.

    Other countries facing declining letter amounts have made reforms Germany and the Netherlands privatized their national postal companies over a decade ago, and other European countries have followed suit. Britain floated shares of the Royal Mail on its stock exchange in 2013. Some countries, such us Sweden and New Zealand, have not privatized their national postal companies, but they have opened them up to competition.

    These reforms have driven efficiency improvements in all of these countries. Additional number of workers have been reduced, productivity has risen and consumers have benefited. Also, note that cost-cutting measures—such as closing tone post offices—are good for both the economy and the environment.

    Privatization and competition also encourage new changes. When the USPS monopoly over "extremely urgent" mail was stopped in 1979, we saw an explosion in efficient overnight private delivery by firms such as FedEx.

    The government needs to wake up to changing technology, study postal reforms abroad and let businessmen reinvent our out-of-date postal system.

    The African elephant, the largest land animal remaining on earth , is of great importance to African ecosystem(生态系统). Unlike other animals, the African elephant is to a great extent the builder of its environment. As a big plant-eater, it largely shapes the forest-and-savanna(大草原)surroundings in which it lives, therefore setting the terms of existence for millions of other animals that live in its habitat(栖息地).

    It is the elephant's great desire for food that makes it a disturber of the environment and an important builder of its habitat. In its continuous search for the 300 pounds of plants it must have every day, it kills small trees and underbushes, and pulls branches off big trees. This results in numerous open spaces in both deep tropical forests and in the woodlands that cover part of the African savannas. In these open spaces are numerous plants in various stages of growth that attract a variety of other plant-eaters.

    Take the rain forests for example. In their natural state, the spreading branches overhead shut out sunlight and prevent the growth of plants on the forest floor. By pulling down trees and eating plants, elephants make open spaces, allowing new plants to grow on the forest floor. In such situations, the forests become suitable for large hoofed plant-eaters to move around and for small plant-eaters to get their food as well.

    What worries scientists now is that the African elephant has become an endangered species. If the elephant disappears, scientists say, many other animals will also disappear from vast areas of forest and savanna, greatly changing and worsening the whole ecosystem.

    We could say that any animal that knows how to find food, avoid being eaten, and raise babies is pretty smart. But can animals learn and remember or can they solve problems?

Many animals have good memories for where food is — a useful skim Scrub jays (灌丛鸦) may be the champions. In one experiment, scientists put them in pre-made holes. After the jays had hidden some food, they were taken out. Scientists mapped where the food was hidd6n and then remove ii, which meant the jays couldn't find the holes by smell. But when the jays came back again, they went right to the hiding they had used. In the wild, they remember where thousands of holes arc. Could you do that?

    Another important smart skill is being able to spot shapes and generalize. This kind of test work best with animals that see well and are interested in pictures. Call in the pigeons(鸽子)! In this test, pigeons had to learn to pick out photos with trees in them, and to ignore photos that didn't include any trees. Once they had learned the rules, they were very adept at it.

    Scientists have to be careful when they test animals for smarts, and the person giving the test has to know the animal really well, in one experiment, a few bananas were hung out of reach over a p on the ground. Monkeys figured out right away how to get the bananas: pick up a stick and knocked down. But clever elephants kept failing this test. Finally scientists figure out why. An elephant's trunk work as both its hand and its nose. When it got the stick, it couldn't smell the bananas. When the elephants were given a couple of boxes instead, they quickly use them to make a step and got the bananas.

    As we're learning, the world is full of smart animals, each thinking in its own special way.

    Diet Coke, diet Pepsi, diet pills, no-fat diet, vegetable diet… We are surrounded by the word “diet” everywhere we look and listen. We have so easily been attracted by the promise and potential of diet products that we have stopped thinking about what diet products are doing to us. We are paying for products that harm us psychologically (心理) and physically.

    Diet products greatly weaken us psychologically. On one level, we are not allowing our brain to admit that our weight problems lie not in actually losing the weight, but in controlling the amount of fatty, high-calorie, unhealthy foods. Diet products allow us to jump over the thinking stage and go straight for the scale(秤) instead. All we have to do is to recognize the word “diet” in food labels.

    On another level, diet products have greater psychological effects. Every time we have a zero-calorie drink, we are telling ourselves without our awareness that we don't have to work to get results. Diet products make people believe that gain comes without pain, and that life can be without struggle.

    The danger of diet products lies not only in the psychological effects they have on us, but also in the physical harm that they cause. Diet foods can indirectly harm our bodies because eating them instead of healthy foods means we are preventing our bodies from having basic nutrients. Diet foods and diet pills contain zero calorie only because the diet industry has created chemicals to produce these wonder products. Diet products may not be nutritional, and the chemicals that go into diet products are possibly dangerous in the future.

    Now that we are aware of the effects that diet products have on us, it is time to seriously think about buying them. Losing weight lies in the power of minds, not in the power of chemicals. Once we realize this, we will be much better able to resist diet products, and therefore prevent the psychological harm that comes from using them.

    By now, we are all aware that social media has had a powerful influence on our culture, in business, on the world at large. Social media websites revolutionized the way people communicate and socialize on the Web. However, besides seeing your friends' new baby on Facebook, or reading about Justin Bieber's latest conflict with the law on Twitter, what are some of the real influences?

    Social networks offer the opportunity for people to reconnect with their old friends and acquaintances, make new friends, share ideas and pictures, and many other activities. Users can keep pace with the latest global and local developments, and take part in campaigns and activities of their choice. Professionals use social media sites like Linkedln to improve their career and business development. Students can work together with their peers to improve their academic and communication skills.

    Unfortunately, there are a few downsides too to social networking. If you are not careful, immoral people can target you for cyber bullying(网络欺凌) and disturbance on social sites. School children, young girls, and women can fall victim to online attacks which can create tension and suffering. If you are a victim of cyber bullying, do not take it lying down, but try to take appropriate legal action against the attacker.

    Many companies have blocked social networks as addicted employees can distract (分心)themselves on such sites, instead of focusing on work. In fact, studies show that British companies have lost billions of dollars per year in productivity because of social media addiction among employees.

    Also, what you carelessly post on the Net can come back to trouble you. Leaking personal information on social sites can make users easily harmed to crimes like identity theft, stalking(尾随犯罪), etc. Many companies perform a background check on the Web before hiring an employee.  If a potential employee has posted something embarrassing on social media, it can greatly affect their chances of getting the job. The same holds true for our relationships too, as our loved ones and friends may get to know if we post something undesirable on social networks.

    Social media has its advantages and drawbacks as each coin has two sides. It is up to each user to use social sites wisely to improve their professional and social life, and exercise caution to ensure they do not fall victim to online dangers.

A Competitive Sport

    Cheerleading

    Over the years, cheerleading has taken two primary forms: game-time cheerleading and competitive cheerleading. Game-time cheerleaders' main goal is to entertain the crowd and lead them with team cheers, which should not be considered a sport. However, competitive cheerleading is more than a form of entertainment. It is really a competitive sport.

    Competitive cheerleading includes lots of physical activity. The majority of the teams require a certain level of tumbling (翻腾运动) ability. It's a very common thing for gymnasts, so it's easy for them to go into competitive cheerleading. Usually these cheerleaders integrate lots of their gymnastics experience including their jumps, tumbling, and overall energy. They also perform lifts and throws. This is where the “fliers” are thrown in the air, held by “bases” in different positions that require strength and working with other teammates.

    Competitive cheerleading is also an activity that is governed by rules under which a winner can be declared. It is awarded points for technique, creativity and sharpness. Usually the more difficult the action is, the better the score is. That's why cheerleaders are trying to experience great difficulty in their performance.

    Besides, there is also a strict rule of time. The whole performance has to be completed in less than three minutes and fifteen seconds, during which the cheerleaders are required to stay within a certain area. Any performance beyond the limit of time is invalid.

    Another reason for the fact that competitive cheerleading is one of the hardest sports is that it has more reported injuries. According to some research, competitive cheerleading is the number one cause of serious sports injuries to women. Emergency room visits for it are five times the number than for any other sport, partially because cheerleaders don't use protective equipment. Smiling cheerleaders are thrown into the air and move down into the arms of the teammates, which may easily cause injuries. Generally, these injuries affect all areas of the body, including wrists, shoulders, ankles, head, and neck.

    There can be no doubt that competitive cheerleading is a sport with professional skills. Hopefully, it will appear in the Olympics since cheerleaders are just as athletic and physically fit as those involved in the more accepted sports. It should be noted that it is a team sport and even the smallest mistake made by one teammate can bring the score of the entire team down. So without working together to achieve the goal, first place is out of reach.

    Last week, my granddaughter started kindergarten, and I wished her every success. But part of me didn't. I actually wanted her to fail in some ways because I believe that failure can be good for our learning process. Success is proving that you can do something that you already know you can do, or doing something correctly the first time, which can often be a problematic victory. First-time success is usually a luck. First-time failure, however, is supposed to be the natural order of things. Failure is how we learn.

    In Africa they describe a good cook as “she who has broken many pots”. If you've spent enough time in the kitchen to have broken a lot of pots, probably you know a fair amount about cooking. I once had dinner with a group of cooks, and they spent time comparing knife wounds and bum scars. They knew how much their failures gave them.

    I earn my living by writing a daily newspaper column. Each week I know that one column I write is going to be the worst column. I try my best every day. I have learned to love that column. A successful column usually means that I am discussing my familiar topic, writing in a style I am used to or saying the same things as anyone else but in a better way.

    My younger daughter is a trapeze artist（荡秋千演员）. She spent three years practicing a show, and she did it successfully for years. There was no reason for her to change it but she did anyway. She said she was no longer learning anything new and she was bored. She risked failure and great public embarrassment in order to feed her soul.

    My granddaughter is a perfectionist. She will feel her failures, and I will want to comfort her. But I will also, I hope, remind her of what she learned, and how she can do better next time.

    In February, 2015, a South Korean woman was sleeping on the floor when her robot vacuum ate her hair, forcing her to call for emergency help. It surely isn't what Stephen Hawking warned us that intelligent devices “mean the end of the human race”. But it does highlight one of the unexpected dangers of inviting robots into our home.

    There are many examples of intelligent technology going bad, but more often than not, they involve cheating rather than physical danger. Meanwhile, increasing evidence suggests that we, especially children, tend to tell our deepest, darkest secrets to human robots. So how do we protect ourselves from giving-away code?

    Once you've invited a robot into your home, you need to manage your expectations. Movies and marketing may have told us to expect deep interaction with robots friends but we've still got a long way to go before they are as socially aware as described. Given the gulf between expectation and reality, it's important to avoid being tricked.

    The message is clear: as robots became increasingly connected to the internet, and able to respond to natural language, you need to especially cautious about figuring out who or what you are talking about.

    We also need to think about how information is being stored and shared when it comes to robots that can record our every move. Some recording devices may have been designed for entertainment but can easily be adapted for more dangerous purposes. Take Nixie, the wearable camera that can fly off your wrist at a moment's notice and take shots around you in the air. It doesn't take much imagination to see how such technology could be taken advantage of.

    If the technology around us is able to record and process speech, images and movement, or listen secretly to us, what will happen to that information? Where will it be stored? Who will have access?

    So, what is the safest way to welcome robots into our homes, public spaces, and social lives? We should be cautiously optimistic that intelligent machines could become enriching companions, while acknowledging that we need to determine strict boundaries for robots. There should be someone to turn to should your robot commit a crime, steal your card... or try to eat your hair.

    Have you ever lost your car on a parking lot? You don't have a clue where your car is after shopping. Then you start walking around clicking on your car keys so the alarm goes off. It can be annoying, especially on a hot sunny day.

    No, you needn't install (安装) an expensive GPS system to keep track of your car. That's too expensive. You would need to pay a monthly fee to use it.

    But is there a way to track your vehicle without spending a fortune? Yes, now there is! A California-based company has created a tiny device that works with your smartphone, which could be exactly what you're looking for!

    What is it?

    It's called TrackR. It is a state-of-the-art tracking device the size of a coin. It's changing the way we keep track of the important things in our lives.

    How does it work?

    It's easy! Install the free TrackR app on your smartphone, connect the app to your device and you're ready to go! Simply attach TrackR to whatever you want to keep an eye on. The entire process of setting it up only takes 5 minutes or less.

    You can attach it to your keys, briefcase, wallet, your latest tech gadgets and anything else you don't want to lose. Then use the TrackR app to locate your missing item in seconds.

    If you forget where you have parked your car, pull out your smartphone and open the TrackR app. Tap on the “find device” button on the screen and the app will tell you the exact spot of the last known location of the TrackR.

    What else can I do with TrackR?

    The device is small and unnoticeable enough that you can attach it to your pet. Put it on their collar, and the issue of searching for them when they run away to nearby places will be over! You'll never waste a minute searching the whole house for it.

    TrackR even comes with a double-sided glue (胶水) so you can stick it to your laptop or under your bike seat. Track down and punish the thieves who steal your expensive things!

    How much does it cost?

    You're probably thinking that this device is very expensive. False! TrackR only costs $29! That's a small price to pay for peace of mind, isn't it?

    Where can I buy one?

    You can buy it directly from the company's website by clicking here //buy. thetrackr. co/gu/special- offers/15/.

How Room Designs Affect Our Work and Feelings

    Architects have long had the feeling that the places we live in can affect our thoughts, feelings and behaviors. But now scientists are giving this feeling an empirical（经验的，实证的） basis. They are discovering how to design spaces that promote creativity, keep people focused and lead to relaxation.

    Researches show that aspects of the physical environment can influence creativity. In 2007, Joan Meyers-Levy at the University of Minnesota, reported that the height of a room's ceiling affects how people think. Her research indicates that higher ceilings encourage people to think more freely, which may lead them to make more abstract connections. Low ceilings, on the other hand, may inspire a more detailed outlook.

    In additions to ceiling height, the view afforded by a building may influence an occupant's ability to concentrate. Nancy Wells and her colleagues at Cornell University found in their study that kids who experienced the greatest increase in greenness as a result of a family move made the most gains on a standard test of attention.

    Using nature to improve focus of attention ought to pay off  academically, and it seems to, according to a study led by C. Kenneth Tanner, head of the School Design & Planning Laboratory at the University of Georgia. Tanner and his team found that students in classrooms with unblocked views of at least 50 feet outside the window had higher scores on tests of vocabulary, language arts and maths than did students whose classrooms primarily overlooked roads and parking lots.

    Recent study on room lighting design suggests than dim（暗淡的） light helps people to loosen up. If that is true generally, keeping the light low during dinner or at parties could increase relaxation. Researchers of Harvard Medical School also discovered that furniture with rounded edges could help visitors relax.

    So far scientists have focused mainly on public buildings. "We have a very limited number of studies, so we're almost looking at the problem through a straw（吸管）," architect David Allison says. "How do you take answers to very specific questions and make broad, generalized use of them? That's what we're all struggling with."

    British scientists have discovered the willow trees planted at an angle could increase sugars for biofuel production.

    Willow is a fast-growing species. It is already used to produce fuels for the renewable heating and power market. In future it could also help to produce biofuel to power vehicles. It has been known that when willows growing in the wild are blown sideways, they tend to produce more sugars. But for a while it has not been known why this happens.

    Researchers at Imperial College London, led by Dr Nicholas Brereton and Dr Michael Ray of the Department of Life Sciences, have now solved the mystery. When the tree is blown sideways, its genes (基因) produce large numbers of sugar molecules (分子) to straighten the tree upwards.

    “This is an important breakthrough. Our study now shows that natural genetic changes are related to these differences. And this could well be the key to unlocking the future for green energy from willow,” said Dr Brereton.

    The research was carried out under lab conditions. The willows were grown at an angle of 45 degrees. They were compared to willows which grow naturally straight upwards. The team then looked for the same effect among the willows growing on the Isle of Orkney where strong winds cause the trees to bend at extreme angles. They discovered that the Orkney trees produce five times the amount of sugars found in willows grown in sheltered conditions.

    Willow is widely planted across the UK. The results show that biofuel crops such as willows could be grown in climatically changeable conditions where chances of growing food crops are limited.

    The study is published in Biotechnology for Biofuels.

    Halloween is a holiday full of tricks and treats and all things frightening and fun. But what happens when you trade your sweets for a scare? The result is always healthier than candy.

    Being frightened can be good for you. Think about your favorite scary books or movies. You are scared but you just can't resist reading or watching them. Being frightened makes your brain flood with healthy chemical substances that excite your mood and release feelings of great excitement.

    When you're frightened, your body also produces a chemical called oxytocin, which helps people bond with one another. So, if you're at a haunted(闹鬼的) house with some pals, that experience can help strengthen your friendship. “Watch people walking out of a haunted house, and you'll see lots of smiles and high fives,” says Dr. Margee Kerr, a sociologist who studies fear.

    There is also some evidence that being scared can help a person manage stressful situations. Things like giving a presentation in front of your class or performing in a school play can make us fearful and anxious. But these experiences help build a sort of endurance to fear that makes us more confident. “You become more comfortable with the physical experience of fear, and so you're better able to work through it during tense situations,” Kerr explains.

    Though some haunting may be healthy, it's important to remember that people experience fear in different ways. What may be fun for one person could be too scary for another. And Kerr notes that kids younger than six and or seven can't separate real and make-believe, so seeing something frightening could have lasting, negative effects.

    Throughout history, music spread among people of different cultures. In today's technological advanced society, however, people spread music online, sometimes without an artist's permission. This can lead to many problems, and music companies are now cracking down on this practice. Sharing music online without permission is theft (盗窃).

    Sharing music online prevents recording companies from making money from their efforts. They say that sharing music online has resulted in a huge drop in profits and sales over the past 10 years. People who find music for free online are not paying for CDs or every MP3 downloaded. To truly understand the influence of music piracy (盗版) on creators, one must understand how many people are involved in the recording process. For the sale of each album, profits must be shared between musicians, sound engineers, music producers, managers, advertisers, and the company selling the product. Many people believe sharing music only affects the recording artist, but the reality is that sharing hurts business for all companies involved.

    There are many people who don't see the harm in sharing music online and even think they have the right to do it. One online blogger states that he originally paid for an entire CD and that he should be able to do with the material whatever he wants. While he may have legally paid for the music, he does not have the right to provide permission, which means people like the blogger are thieves.

    Although we don't spread today's music the same way we did before, there's no doubt that people around the world love to share music. However, internet piracy would prevent musicians from continuing producing albums for fear of theft. Therefore, if people want to continue listening to their favorite artists, they need to buy their music so that artists will make enough profit to continue their music careers.

    The new social robots, including Jibo, Cozmo, Kuri and Meccano M.A.X., bear some similarities to assistants like Apple's Siri, but these robots come with something more. They are designed to win us over not with their smarts but with their personality. They are sold as companions that do more than talk to us. Time magazine cheered for the robots that "could fundamentally reshape how we interact with machines." But is reshaping how we interact with machines a good thing, especially for children?

    Some researchers in favor of the robots don't see a problem with this. People have relationships with many kinds of things. Some say robots are just another thing with which we can have relationships. To support their argument, roboticists sometimes point to how children deal with toy dolls. Children animate (赋予…生命) dolls and turn them into imaginary friends. Jibo, in a sense, will be one more imaginary friend, and arguably a more intelligent and fun one.

    Getting attached to dolls and sociable machines is different, though. Today's robots tell children that they have emotions, friendships, even dreams to share. In reality, the whole goal of the robots is emotional trickery. For instance, Cozmo the robot needs to be fed, repaired and played with. Boris Sofman, the chief executive of Anki, the company behind Cozmo, says that the idea is to create "a deeper and deeper emotional connection ... And if you neglect him, you feel the pain of that." What is the point of this, exactly? What does it mean to feel the pain of neglecting something that feels no pain at being neglected, or to feel anger at being neglected by something that doesn't even know it is neglecting you?

    This should not be our only concern. It is troubling that these robots try to understand how children feel. Robots, however, have no emotions to share, and they cannot put themselves in our place. No matter what robotic creatures "say", they don't understand our emotional lives. They present themselves as empathy machines, but they are missing the essential equipment. They have not been born, they don't know pain, or death, or fear. Robot thinking may be thinking, but robot feeling is never feeling, and robot love is never love.

    What is also troubling is that children take robots' behavior to indicate feelings. When the robots interact with them, children take this as evidence that the robots like them, and when robots don't work when needed, children also take it personally. Their relationships with the robots affect their self-esteem (自尊). In one study, an 8-year-old boy concluded that the robot stopped talking to him because the robot liked his brothers better.

    For so long, we dreamed of artificial intelligence offering us not only simple help but conversation and care. Now that our dream is becoming real, it is time to deal with the emotional downside of living with robots that "feel".

    Welcome to your future life. It's 2035. You have a job, a family and you're about 40 years old.

    Getting ready for work, you stand in front of the mirror, "Turn red, "you say. Your shirt changes from sky blue to deep red. Tiny preprogrammed electronics are rearranged(重新设置)in your shirt to change its colour. Looking into the mirror, you find it hard to believe that you are 40. You look much younger. With amazing advances in medicine, people in your generation may live to be 150 years old. You're not even middle-aged.

    As you go into the kitchen and prepare to pour your breakfast cereal(谷类) into a bowl, you hear:" To lose weight, you shouldn't eat that," from your shoes. They read the tiny electronic code on the cereal box to find out the nutrition details. You decide to listen to your shoes. "Kitchen, what can I have for breakfast?" A list of possible foods appears on the counter as kitchen checks its food supplies.

    "Ready for your trip to space. You ask your son and daughter." In 2005 only specially trained astronauts went into space—and very few of them. Today anyone can go to space for day trips or longer vacation. Your best friend even works in space. Handing your children three strawberries each, you add, "The doctor said you need these for space travel." Thanks to medical advices, vaccination shots(疫苗注射)are a thing of the past. Ordinary foods contain specific vaccines. With the berries in their mouths, the kids head for the front door.

    It's time for you to go to work. Your car checks your fingerprints and unlocks the doors. "My office. Autopilot(自动驾驶), " you command. Your car drives itself down the road and moves smoothly into traffic on the highway. You sit back and unroll your e-newspaper. The latest news downloads and fills the viewer. Looking through the pages, you watch the news as video films rather than read it.

California has lost half its big trees since the 1930s, according to a study to be published Tuesday and climate change seems to be a major factor(因素).

The number of trees larger than two feet across has declined by 50 percent on more than 46, 000 square miles of California forests, the new study finds. No area was spared or unaffected, from the foggy northern coast to the Sierra Nevada Mountains to the San Gabriels above Los Angeles. In the Sierra high country, the number of big trees has fallen by more than 55 percent; in parts of southern California the decline was nearly 75 percent.

Many factors contributed to the decline, said Patrick Mclntyre, an ecologist who was the lead author of the study. Woodcutters targeted big trees. Housing development pushed into the woods. Aggressive wildfire control has left California forests crowded with small trees that compete with big trees for resources(资源).

But in comparing a study of California forests done in the 1920s and 1930s with another one between 2001 and 2010, Mclntyre and his colleagues documented a widespread death of big trees that was evident even in wildlands protected from woodcutting or development.

The loss of big trees was greatest in areas where trees had suffered the greatest water shortage. The researchers figured out water stress with a computer model that calculated how much water trees were getting in comparison with how much they needed, taking into account such things as rainfall, air temperature, dampness of soil, and the timing of snowmelt(融雪).

Since the 1930s, Mclntyre said, the biggest factors driving up water stress in the state have been rising temperatures, which cause trees to lose more water to the air, and earlier snowmelt, which reduces the water supply available to trees during the dry season.

The man who invented the World Wide Web a few decades ago is calling for major changes to make it better for humans. In an open letter published on Tuesday, Berners-Lee said that the web was used by half the world's population.

Berners-Lee said the web had clearly created great opportunities for humans to progress and had made life easier for millions of people. Actually, it also has offered opportunities to groups traditionally not heard a new voice in society. However, he added that the web had also provided new ways for cheats to commit crimes (犯罪).

"Against the background of news stories about how the web is misused, it's understandable that many people feel afraid and unsure if the web is really a force for good," he wrote.

Berners-Lee created a group called the World Wide Web Foundation. He is looking for help from governments, companies and people to become more involved in shaping the web to do more good for humans. His actual plan is called the "Contract (合同) for the Web".

Under this contract, governments are called on to take steps to make sure all people can connect to the Internet and that personal privacy is respected. Businesses are asked to keep the Internet prices low so more people can use the web. In addition, companies should respect privacy and develop technologies that aim to put people first.

The plan also calls on people to create materials for the web and work with others to make sure that is rich, quality information for everyone. Besides, people should seek to "build strong communities that respect personal speech and human equality." "The path to make the Internet better is the responsibility of everyone who uses it," Bermers-Lee added, "Making big changes will not be easy, but will be very well worth it in the end."