In London's art gallery six or seven men, mostly in their 30s, are busy painting the walls with new designs in colorful lettering and clever tricks. Tins of spray paint and beer stand on the ground. The atmosphere is not unlike that of a golf course: a mix of concentration and relaxation.

    Graffiti(涂鸦) painting is traditionally a daring hobby. Teenagers avoid security guards to put their names on trains and buses. But over the past decade that has almost disappeared from Britain's cities. Between 2007 and 2017 the number of incidents of graffiti recorded by the British Transport Police fell by 63%. A survey by the environment ministry shows that fewer places are damaged by tags(绘名) than ever. Graffiti are increasingly limited to only a few walls. In time the practice may die out entirely.

    The most obvious reason for the decline in tagging and train-painting is better policing, says Keegan Webb, who runs The London Vandal, a graffiti blog (博客). Numerous cameras mean it is harder to get away with painting illegally. And punishments are more severe. A generational change is apparent, too. Now teenagers prefer to play with iPads and video games. Those who do get involved tend to prefer street art to graffiti. And the internet helps painters win far more attention by posting pictures online than they can by breaking into a railway yard.

    Taggers and graffiti artists mostly grew up in the 1980s and 1990s. Those men are now older and less willing to take risks. "We can't run away from the police any more," says Ben Eine, who turned from tagging to street art. The hip-hop culture that inspired graffiti in the first place has faded. Video games and comic books provide more inspiration than music.

    Graffiti may eventually disappear. But for now the hobby is almost respectable. Mr Eine says he has lots of friends who used to paint trains. Now with wives and children, they paint abandoned houses at the weekend. It has become something to do on a Sunday afternoon—a slightly healthier alternative to sitting watching the football.

    Scientists have found living organisms trapped in crystals (晶体) that could be 50,000 years old.

    The organisms were found in a hot, but beautiful cave system in Naica, Mexico. These ancient life forms can be seen only with a microscope. Penelope Boston, who leads the Astrobiology Institute at NASA, the space agency of the United States, says the ancient microbes were able to live by eating minerals such as iron.

    She spoke about the discovery recently at a meeting of the American Association for the Advancement of Science. If the findings are confirmed, they will show how microbes can survive in extreme conditions. Forty different kinds of microbes and some viruses were found in the underground area. The genetic structures of these organisms are 10 percent different from those of their nearest relatives.

    The caves in Naica are 800 kilometers deep. They were once used for mining lead. Before the miners began working in the caves, the area was separated from the surface and the outside world. Some of the caves are as big as the large religious centers built during Europe's Middle Ages. There are crystals covering the walls. The caves are so hot that scientists must wear special clothing to keep cool. The clothing keeps the crystals safe from human germs (病菌) or other damage. Boston said the researchers could only work for about 20 minutes at a time before they had to go to a room that was 38 degrees Celsius to cool down.

    NASA officials would not let Boston share her findings with scientific experts before last week's announcement. So scientists could not say much about the findings. But Norine Noonan, a biologist with the University of South Florida, said she believed them. “Why are we surprised?”Noonan asked. “ As a biologist, I would say life on Earth is extremely tough and extremely colorful.”

    Boston is also studying microbes commonly found inside caves in other countries, such as Ukraine and the United States. These microbes appear to be impossible to kill. Boston said they show how difficult life on Earth can be.

    An Indian movie about two sisters has become a huge hit in China. The Hindi language film, called Dangal, has earned almost $ 170 million in China since its release there on May 5.

    Much has been written about why Dangal has enjoyed such big success in China. Some people say one reason is that the film's star and producer, Aamir Khan. He is famous in India's Bollywood film industry. Two of his earlier films were also big hits in China.

    Khan's popularity was clear after he got more than 600,000 followers on the Chinese social media service Sina Weibo within two months of joining. But he is not the only reason that the Him strongly connects with audience across China. Media has pointed out how it shows similarities between parental systems in China and India.

    Dangal is based on the true story of a man who enjoyed the sport of wrestling (摔跤). He competed as a wrestler, but never could achieve his lifelong dream: winning a gold medal. As a father, he wanted his son to win the medal. But his wife only gives birth to daughters. So he finally decides to train them to be world-class wrestlers.

    The movie is more serious than most Bollywood productions, which tell happy love stories and include colorful music and dance performances.

    Edward Chan is a professor at the Hong Kong Polytechnic University. He says the strict way of parenting in the film is something people in China can easily relate to. “I think the father role described by the movie in India is quite similar to the culture, especially the traditional culture in China.”

    The Chinese government-supported Global Times newspaper pointed that movie critics (评论家) in China did not like Dangal. Most of them agree with the fact that the father in the film was forceful in pushing his daughters to become wrestlers. But the film Dangal is really aimed to educate children to work for their dreams.

    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.

    Do you want to live another 100 years or more? Some experts say that scientific advances will one day enable humans to last tens of years beyond what is now seen as the natural limit of the human life span.

    "I think we are knocking at the door of immortality(永生)," said Michael Zey, a Montclair State University business professor and author of two books on the future. "I think by 2075 we will see it and that' s a conservative estimate(保守的估计)."

    At the conference in San Francisco, Donald Louria, a professor at New Jersey Medical School in Newark said advances in using genes as well as nanotechnology(纳米技术) make it likely that humans will live in the future beyond what has been possible in the past. "There is a great effort so that people can live from 120 to 180 years," he said. "Some have suggested that there is no limit and that people could live to 200 or 300 or 500 years."

    However, many scientists who specialize in aging are doubtful about it and say the human body is just not designed to last past about 120 years. Even with healthier lifestyles and less disease, they say failure of the brain and organs will finally lead all humans to death.

    Scientists also differ on what kind of life the super aged might live. "It remains to be seen if you pass 120, you know; could you be healthy enough to have good quality of life?" said Leonard Poon, director of the University of Georgia Gerontology Centre. "At present people who could get to that point are not in good health at all."

    People can't see you when you're speaking on the phone, but they can hear you. So, the way you speak is especially important. In fact, researchers have calculated that 80% of communication over the phone is through your tone of voice; and only 20% is from the words you use. Here are our top tips on how to speak over the phone.

    ①Facial Expressions

    Your facial expression can influence your voice. For example, if you smile, your voice will sound warm and friendly, just the opposite, if you have an angry look on your face, it can make you sound unpleasant.

    ②Volume

    If you speak too loudly, you could sound angry. And if you speak too softly, it'll be difficult to hear you. So, speak loudly enough to be heard clearly, but not so loud that you're shouting.

    ③Pace

    The pace of your voice is how quickly you speak. And this can show how you feel. For example, an angry person might speak faster than normal. Or a downhearted person might speak very slowly. Try speaking a little more slowly than normal. This will make you sound confident, and it'll make it easier for the other person to understand you.

    ④Gestures

    Gesturing can influence the tone of your voice. When you gesture, you bring more air into the lungs, which can make your voice sound warmer. Gestures are also useful to help you stress the right words or even find the words you need. The best thing about gesturing during a phone call is that no one can see what you're doing, so you can gesture as wildly as you like!

    ⑤Movement

    If you're feeling nervous, stand up and move around. It will reduce the nervousness in your body and help your voice to sound more confident.

    ⑥Pauses (停顿)

    Using pauses every now and then can help you to slow down. This will make you sound more confident and in control. Also, if you pause after giving some new information, it'll give the other person time to understand it. At the same time, listen to how the other person uses pauses. They could tell you something about the speaker's feeling. For example, when a speaker is really angry, he might use pauses and says, "I…am…so…angry…"