For many people around the world, a subway journey means speeding from one dull station to the next, surrounded by too many uncomfortable, impatient people. But on the Moscow Metro, taking the subway is like walking through a national heritage site. Depending on where you get off, you'll receive a brief course in architectural movements and face colorful glass windows, marble(大理石) columns, gilded(鎏金的) mosaics and painted scenes from Russian history.

    “These extraordinarily beautiful places are unlike any metro station I've ever seen, “says Vancouver-based photographer David Burdeny.

    When Burdeny, who himself has a master's degree in architecture, first found out about Moscow's metro stations, he was struck by the work of art. In all, he has photographed 20 of the most beautiful stations.

    Burdeny had originally planned to focus on Russian stations more generally, taking photos of examples in both St. Petersburg and Moscow.

    “But when I saw the stations in Moscow, they just completely blew away the St. Petersburg ones,” he says.

    Shooting in the subway sounds simple, but it is not without challenges. For one thing, Burdeny had to figure out a way to access them between 00:30 a.m. and 5:30 a.m., when the stations were closed.

    In the end, he settled on Arbatskaya Metro Station, whose vaulted(拱状的) arches he found the most beautiful. But it also represented a challenge he was not sure if he was able to overcome: conveying the hugeness of the spaces. The Arbatskaya platform, for example, stretches 820 feet.

    “Some of the arches are quite long,” he says. “When you enter them, they're just so completely grand.”

    Grown­ups are often surprised by how well they remember something they learned as children but have never practiced ever since. A man who has not had a chance to go swimming for years can still swim as well as ever when he gets back in the water. He can get on a bicycle after many years and still ride away. He can play catch and hit a ball as well as his son. A mother who has not thought about the words for years can teach her daughter the poem that begins “Twinkle, twinkle, little star” or remember the story of Cinderella or Goldilocks and the Three Bears.

    One explanation is the law of overlearning, which can be stated as follows: Once we have learned something, additional learning trials(尝试)increase the length of time we will remember it.

    In childhood we usually continue to practice such skills as swimming, bicycle riding, and playing baseball long after we have learned them. We continue to listen to and remind ourselves of words such as “Twinkle, twinkle, little star” and childhood tales such as Cinderella and Goldilocks. We not only learn but overlearn.

    The multiplication tables(乘法口诀表)are an exception to the general rule that we forget rather quickly the things that we learn in school, because they are another of the things we overlearn in childhood.

    The law of overlearning explains why cramming(突击学习)for an examination, though it may result in a passing grade, is not a satisfactory way to learn a college course. By cramming, a student may learn the subject well enough to get by on the examination, but he is likely soon to forget almost everything he learned. A little overlearning, on the other hand, is really necessary for one's future development.

    We all have dreams sometimes. Some are sweet but some are nightmares. Almost all researchers in sleep explain that nightmares are a reaction to negative experiences that happen during waking hours. However, some of them believe that nightmares do have some real benefits. One 2017 study, for example, found that frequent nightmare sufferers rated themselves as more empathetic（共鸣的）.They also displayed more of a tendency to unconsciously mirror other people through things like yawning. People who have constant nightmares also tend to think further outside the box on psychoanalysis tasks. Some other researchers have found support for the idea that nightmares might be linked to creativity.

    People seeking cure for nightmares were not necessarily more fearful or anxious, but rather had a general sensitivity to all emotional experience. Sensitivity is the driving force behind intense dreams. Heightened sensitivity to threats or fear during the day results in bad dreams and nightmares, whereas heightened passion or excitement may result in more intense positive dreams. And both these forms of dreams may feed back into waking life, perhaps increasing suffering after nightmares, or promoting social bonds and empathy after positive dreams.

    The effects go further still. This sensitivity overflows over into perceptions and thoughts: people who have a lot of nightmares experience a dreamlike quality to their waking thoughts. And this kind of thinking seems to give them a creative edge. For instance, studies show that such people tend to have greater creative talent and artistic expression. And people who often have nightmares also tend to have more positive dreams than the average person.

    The evidence points towards the idea that, rather than disturbing normal activity, people who are unfortunate in having a lot of nightmares also have a dreaming life that is at least as creative, positive and vivid as it can be distressing and terrifying. What's more, this imaginative richness is unlikely to be limited to sleep, but also is filled with waking thought and daydreams. Even after people wake up and shake off the nightmare, in other words, a mark of it stays behind, possessing them throughout the day.

    They already guide blind and disabled people; now dogs are to be trained to help people with dementia(痴呆) or Alzheimer's. Alzheimer's can make people confuse night and day or forget basic things such as washing and drinking enough water.

    The dogs will be trained to respond to sound triggers(触发器) in the home that make them perform tasks. The duties will include reminding their owners to take medicine, as well as encouraging them to eat, drink and sleep regularly.

    The idea was developed by design students at the Glasgow School of Art and will now be put into practice by Alzheimer's Scotland and Dogs for the Disabled. The first dogs will be distributed to four Scottish couples, where one of the partners is in the early stages of dementia. 670,000 people in Britain have dementia and one in three over 65 will develop the condition. By 2021 this is expected rise to one million.

    John Gray of Alzheimer's Scotland said, "People in the early stages of dementia are still able to live a relatively normal life, and dogs help to maintain routine. " Another advantage of using the pets as companions is that dogs can give them a sense of silent support and companionship. Ms Gray said: "The evidence is that people may forget familiar faces but not pets. It's such a strong bond that people often remember them longest. People don't need to communicate verbally(口头上) but they can still interact. You can have a speechless bond."

    Helen McCain, director of Dogs for the Disabled, said, "People with dementia often forget to take medicine. If a dog presents them with a bag with pills in it, there is a greater chance of them taking it. The dogs would also encourage the owners to take them out for walks, ensuring they keep exercising and interacting with other people."

    They train four hours a day, often waking up at 4:30 or 5:00 for before-school practices. Their evenings and weekends are eaten up by twice-weekly travel games. Every day is the same; there's no break. No, these aren't Olympic athletes; they're kids.

    The benefits of sports are obvious. So, it's not surprising that, according to CNN, 41 million American children play competitive sports. But when does this become too much of a good thing?

    Seven years ago, a survey in Sporting Kid magazine found 84 percent of athletes' parents had observed belligerent behavior in other parents at games and that 80 percent had been targets of this behavior. What does this say about sports culture, and our culture as a whole? Some parents have become so crazy about their children's winning that they don't stop to think about what example they are setting.

    If athletes are constantly surrounded by adults who scream at coaches and attack sports officials, they may think that this is acceptable behavior. They'll try to win at all costs. In other words, they won't know how to accept defeat, and learn from it.

    The amount of time some athletes spend practicing can be dangerous. According to Sports Illustrated, over 3.5 million athletes younger that 15 suffered from a sports-related injury—that's nearly one in ten! Many injuries cause permanent（永久的）damage if not treated.

    So what can we do about this situation? Some argue that there is no problem, because sports has always been and will always be competitive. But did your grandparents spend hours each day practicing tennis or volleyball? No, they probably played with the neighborhood kids after school, not worrying about winning. All they wanted was to have fun. And that's what we need to change in youth sports—focus on enjoyment.

    A scientist once said: "I have concluded that the earth is being visited by intelligently controlled vehicles from outer space."

    If we take this as a reasonable explanation for UFOs (unidentified flying objects), questions immediately come up.

    "Why don't they get in touch with us, then? Why don't they land right on the White House lawn and declare themselves?" people asked.

    In reply, scientists say that, while this may be what we want, it may not necessarily be what they want.

    "The most likely explanation, it seems to me," said Dr. Mead, "is that they are simply watching what we are up to—that responsible society outside our solar system is keeping an eye on us to see that we don't cause a chain reaction that might have unexpected effects for the outside of our solar system."

    Opinions from other scientists might go like this: "Why should they want to get in touch with us? We may feel we're more important than we really are! They may want to observe us only and not interfere(干涉) with the development of our civilization  They may not care if we see them but they also may not care to say 'hello'."

    Some scientists have also suggested that Earth is a kind of zoo or wildlife reserve. Just as we set aside wilderness areas and wildlife reserves to allow animals and growing things to develop naturally while we observe them, so perhaps Earth was set aside ages ago for the same purpose.

    Are we being observed by intelligent beings from other civilizations in the universe? Are they watching our progress in space travel? Do we live in a huge "zoo" observed by our "keepers," but having no communication with them?

    Never before in our history have we had to face ideas bravely like these. The simple fact is that we, who have always regarded ourselves as supreme in the universe, may not be so. Now we have to recognize that, among the stars in the heavens, there may very well be worlds lived by beings who are to us as we are to ants.