It could happen just about any time you step out in public. You get onto an almost-empty bus, but the next passenger in decides to ignore dozens of empty seats to sit right next to you. While you're waiting in line at a supermarket, the next customer insists on standing only two inches behind you and shouting into his cell-phone. You go into a public restroom, and the next person to enter decides to use the next stall. Transgressions(冒犯) like these don't just make us feel uncomfortable; we often feel anxious, alarmed; and violated(被侵犯的). It is the attack of the personal-space invaders.

    In any society, shared definitions of personal space govern how we interact with other people. People living in densely(密集地) populated cities like Mumbai, Beijing, or Mexico City tend to require less personal space than people living in sparsely(稀少地) populated places within the country. In America, New Yorkers often have smaller requirements than residents of western states, like Montana, Shenandoah and Wyoming. Because everyone has different standards, gestures that are innocent in one place can be interpreted as opposite in another, especially in Britain.

    As the British etiquette(礼仪) website Debrett puts it, as a British person, somebody standing too close may make you "focus less on what somebody is saying than on how close they are to you". Simple acts like putting an arm around someone you don't know may seem friendly in China, but they can make us very uncomfortable. People from many European countries such as France and Spain kiss each other on the cheek when they meet, yet to British person, this seems too friendly and "touch-freely". The website explains! "The British are not backslappers(拍人后背的人) and generally do not show affection in public".

    Are British people unfriendly? Far from it. The website adds that they are not as "stand-offish and aloof' as they may seem, but very friendly and helpful to foreigners. However, remember not to be too close. If you are going to come closer than an arm's length, please let them know.

    Dolphins(海豚) live in a dark underwater world. It's often impossible to see each other or anything else around them, so sound plays an important role in their survival. To communicate with each other, dolphins produce all kinds of sounds.

    Only other dolphins understand what the sounds mean. Scientists haven't uncovered their secret communication, except for one kind of whistle. It might last less than a second, but this whistle is a big deal. Why? Because these whistles are actually names of dolphins - and every dolphin has one. Scientists call these sounds a “signature whistle.” When other dolphins hear the whistle, they know which dolphin is calling.

    Dolphins often hunt by themselves but still need to stay connected to the group. Since they can't always see each other, dolphins use their signature whistles to check in with other dolphins hundreds of yards away. “In coastal areas, dolphins exchange whistles even when they're a third of a mile apart,” says Greg Campbell, who studies animals. That means dolphins shout out to group members that might be nearly five football fields away.

    What's amazing is who names the baby dolphin. Not the mother. Not an auntie dolphin or another group member. Scientists believe the baby dolphin itself comes up with the signature whistle. Like human babies, a baby dolphin plays with sounds throughout its first year. While testing its sound skills, a baby dolphin is doing something amazing. It's creating or figuring out its signature whistle. How or why it chooses its signature whistle is not clear. Studies show that most of the time the signature whistle is nothing like its mother's or group members' whistles.

    When the baby dolphin is about a year old, its signature whistle is set. It repeats it often so the other dolphins learn to recognize it.

    Deciphering(破译) dolphin names is just the beginning of figuring out what dolphins communicate about. Do they chat about sharks? Discuss the tides? Maybe they even have a name for people. Someday scientists are to decipher the rest of dolphins' communication.

    Plan on traveling around the USA? There are a number of outstanding websites that can make your American dream come true.

www.101usaholidays.co.uk

    This is the latest offering that features 101 holiday ideas to the USA. It's a diverse selection, ranging from touring in the footsteps of Martin Luther King to a golfing break in Arizona and a cycling and wine-tasting trip in California's Napa Valley. Narrow down what you're looking for—whether by price, region, theme and who will be traveling—and then just the photos of the relevant holidays remain on view. It's a really clever design.

http://byways.org

    The National Scenic Byways Program covers 150 memorable roads. Some are natural scenic routes, such as Route 1 along the California coast. Others focus on history (such as Route 66) or man-made attractions (the Las Vegas Strip). For each, you're provided with a map telling the route's length and how long is allowed.

www.oyster.com

    This is the best website for reviews of hotels in US cities and tourist sites. There are photos of each hotel. Importantly, these are not promotional photos provided by the hotels, but more honest and revealing ones taken by inspectors. From the 243 hotels reviewed in New York, you can narrow down what you are looking for by locations, facilities and styles, or just pick out a selection of the best.

http://seaworldparks.com

    SeaWorld in San Diego can make dreams come true, but the price is not affordable for the majority of people. So turn to long-established http://seaworldparks.com, giving big discounts on tickets, hotel and dining at SeaWorld.

    How can you gain knowledge of the world without books or teachers? Visiting various kinds of world-famous museums may be your best choice. If you are interested ，here are 3 famous museums well worth visiting.
National Gallery, London 2017 attendance: 6,263,000

    The National Gallery originally opened in 1824 in a Pall Mall townhouse with just 38paintings. Today's collection contains over 2, 300 works from the 13th to 19th centuries, which you can appreciate free of charge. The works range in style and time period, but hey, everyone needs to see Van Gogh's Sunflowers in Room 43 at least once, for which the Museum is famous.

    Opening time: daily 10 am—6 pm Friday 10 am—9 pm

    Closed time: January and 24—26 December

    Admission: Free
National Air and Space Museum, Washington, D. C.

    2017 attendance: 7,500,000

    The National Air and Space Museum, part of the Smithsonian Institution, hosts the world's largest collection of aviation and space artifacts. You'll see crowds flocking toward the 1903Wright Flyer and Apollo 11command module, but don't forget about NASA's often—overlooked Stardust probe.

    Hours and Admission :Open every day except December 25.

    Free admission and tickets (free) are needed.

    ⒈A maximum of 4000 free tickets will be issued each day at the museum.

    ⒉Each visitor can once collect one free ticket of the day with valid ID (Passport ).

    Regular Hours :10:00 am to 5:30 pm

    Extended Hours :10:00 am to 7:30pm Fridays, Saturdays and Sundays

National Museum of China, Beijing

    2017 attendance: 7,550,000

    Founded in February 2003, this huge, well-curated museum sits on the edge of Beijing's Tiananmen Square and is free to enter. It houses more than 1.3 million exhibition pieces in its 40halls ，focused primarily on China's achievements in history, culture, and art.

    Opening Hours :9 :00—17:00

    (No Entry after 16:00) Closed on Mondays

    Museum Visiting Tips: Limit the number of bags( only one handbag is allowed ). All visitors are screened through metal detector upon entry. The fewer items you bring inside the Museum. Before you visit, please review the list of prohibited items, Visitors carrying prohibited items will not be allowed inside the Museum, s0 please leave them at home or in your car.

    No Food or Drink: Only bottled water is permitted in the Museum

    Robot are about to enter our lives. From doing housework, entertaining and educating our children, to looking after the elderly, scientists say we will soon be welcoming robots into our homes and workplaces.

    Researchers believe we are on the cusp (过渡点) of a robot revolution that will mirror the quick growth of the computer revolution. They are developing new laws for robot behavior, and designing new ways for humans and robots to communicate.

    “I think robots will change who we are, just as eyeglasses and fire changed who we were before, says Rodney Brooks, a director of the MIT Computer Science and Artificial Intelligence Laboratory.

    Some ideas and technologies may sound like science fiction, but they are fast becoming science fact. Robots scientists invented are already beginning to perform everyday tasks like cleaning our floors. The latest types from Japan are able to help the elderly to get out of bed or get up after a fall. They can also remind them when to take medication (药物), or even help wash their hair.

    “Robot now are not human-like. For example they are things like automatic (自动的) beds and wheelchairs,” says Prof Hiroshi Ishiguro at Osaka University, Japan. He believes the time is coming when robots start looking less like machines, and more like us. “In the near future we are going to use more human-like robots. I really think so, says Prof Ishiguro.

    Prof Maja Mataric at the University of Southern California agrees. “I'm very excited about the fact that today we are trying to make robots that look like human beings,” she says.

    “I believe we love robots because they're reflections (反映) of ourselves,” says Ken Goldberg, director of the Berkeley Center for New Media at the University of California at Berkeley.

    “Robots could be used in education, learning, and healthcare, where social support is important,” says Dr. Cynthia Breazeal, director of the Personal Robots Group at MIT.

    As years went by, I realized that one of the biggest problems of these adults are worry. A large majority of students were businessmen, executives, salesmen, engineers, accountants: a cross section of all the trades and professions—and most of them had problems! There were women in the classes — businesswomen and housewives. They, too, had problems! Clearly, what I needed was a textbook on how to conquer worry—so again I tried to find one.

    I went to New York's great public library at Fifth Avenue and Forty-second Street and discovered to my astonishment that this library had only twenty-two books listed under the title WORRY. I also noticed, to my amusement, that it had one hundred and eighty-nine books listed under WORMS. Almost nine times as many books about worms as about worry! Surprising, isn't it? Since worry is one of the biggest problems facing mankind, you would think, wouldn't you, that every high school and college would give a course on "How to Stop Worrying"?

    Yet, if there is even one course on that subject in any college in the land, I have never heard of it. No wonder David Seabury said in his book How to Worry Successfully: " We grow up with as little preparation for the pressures of experience as a bookworm asked to do a ballet (芭蕾舞)."

    The result? More than half of our hospital beds are occupied by people with nervous and emotional troubles.

    I looked over those twenty-two books on worry, reposing (靠) on the shelves of the New York Public Library. In addition, I purchased all the books on worry I could find; yet I couldn't discover even one that I could use as a textbook in my course for adults. So I decided to write one by myself.