Ideas about polite behavior are different from one culture to another. Some societies, such as America and Australia, for example, are mobile and very open. People here change jobs and move houses quite often. As a result, they have a lot of relationships that often last only a short time, and they need to get to know people quickly. So it's normal to have friendly conversations with people that they have just met, and you can talk about things that other cultures would regard as personal.

    On the other hand, there are more crowded and less mobile societies where long–term relationships are more important. A Malaysian or Mexican business person, for example, will want to get to know you very well before he or she feels happy to start business. But when you do get to know each other, the relationship becomes much deeper than it would in a mobile society.

    To Americans, both Europeans and Asians seem cool and formal at first. On the other hand, as a passenger from a less mobile society puts it, it's no fun spending several hours next to a stranger who wants to tell you all about his or her life and asks you all sorts of questions that you don't want to answer.

    Cross-cultural differences aren't just a problem for travelers, but also for the flights that carry them. All flights want to provide the best service, but ideas about good service are different from place to place. This can be seen most clearly in the way that problems are dealt with.

    Some societies have “universalist” cultures. These societies strongly respect rules, and they treat every person and situation in basically the same way.

     “Particularist” societies, on the other hand, also have rules, but they are less important than the society's unwritten ideas about what is right or wrong for a particular situation or a particular person. So the normal rules are changed to fit the needs of the situation or the importance of the person.

    This difference can cause problems. A traveler from a particularist society, India, is checking in for a flight in Germany, a country which has a universalist culture. The Indian traveler has too much luggage, but he explains that he has been away from home for a long time and the suitcases are full of presents for his family. He expects that the check–in official will understand his problem and will change the rules for him. The check–in official explains that if he was allowed to have too much luggage, it wouldn't be fair to the other passengers. But the traveler thinks this is unfair, because the other passengers don't have his problem.

    Thirteen-year-old American Jessica Goldstone wants to be a fashion designer when she finishes school. She thinks her designs would be more exciting than clothes bought from stores. But until this month, Jessica has never touched a sewing machine(缝纫机).

    After her first class, Jessica and six other girls aged 9 to 13 said that sewing was fun, cool and challenging.

    These students at Fabrics' Sew Fun class show that the sewing machine is becoming popular again.

    “There have been a lot of teens getting excited about sewing,” said a sewing company worker Donna Smith. “Some of them come from the Project Runway TV show,” she said. This TV show is an exciting weekly contest to make a great fashion designer. Every week one contestant (参赛者) fails the test and has to leave the contest.

    The number of people who joined sewing class summer camps grew by 10 percent this year. That's good news for companies that make sewing machines and publish sewing magazines. The Singer Sewing Company sold nearly 3 million sewing machines in the United States last year. This is about twice as many as in 1999.

    Sewing machines have been around for more than 150 years, but they have changed a lot since your grandmother was a girl.

    Spencer Carmel started sewing lessons after getting a sewing machine for her 11^th birthday. She has sewn a lot by hand, but she wants to make more difficult things. Spencer's class recently made hats.

    Another member of the class, Kelsey Oen, 9 years old, needed time to get used to her machine, but soon she could use it well. By the end of the class, Kelsey was happy and wearing her new hat.

    Something's happening at the lowest point on our planet.

The Dead Sea, a salt lake bordered by Jordan to the east and Israel and Palestine to the west, is shrinking(缩小) at an alarming rate—--about 3.3 feet per year, according to the environmentalist group EcoPeace Middle East. And human actions are largely to blame.

    “It's not just like one country is punishing the Dead Sea; it's more like the whole area,” said photographer Mortize Kustner, who visited the area in February to work on his series “The Dying Dead Sea”.

    The Dead Sea needs water from the other natural sources surrounding it, such as the Jordan River basin. But around the 1960s, some of the water sources it relied on were diverted(使改道).Israel, for instance, built a pipeline during that time so it could supply water throughout the country.

    Mineral extraction(开采) industries are another main reason the water levels are falling, experts say. The Dead Sea's minerals have been used as medicine and can often be found in cosmetics(化妆品) and other consumer products.

    And then, of course, there's the Middle East's hot, dry climate, which makes it difficult for the lake to replenish itself.

    Last year, Israel and Jordan signed a $900 million deal in an effort to keep the Dead Sea's water levels stable（稳定）. It includes building a canal from the Red Sea to the Dead Sea which would be able to not only supply water to Israel and Jordan but also to pump water into the Dead Sea.

    But for now, Kustner shows us that the Dead Sea remains very much a place of interest, with people from all over the world going there to swim in its salty waters.

    The Dead Sea, known as the Salt Sea in the language of Hebrew, is one of the saltiest bodies of water in the world. And because of what has been happening over the years, the salt is only getting saltier.

    Here is a record of the discussion about AI (artificial intelligence) conducted by several scientists:

    Scientist A: I would say that we are quite a long way off developing the AI, though I do think it will happen within the next thirty or forty years. We will probably remain in control of technology and it will help us solve many of the world's problems. However, no one really knows what will happen if machines become more intelligent than humans. They may help us, ignore us or destroy us. I tend to believe AI will have a positive influence on our future lives, but whether that is true will be partly up to us.

    Scientist B: I have to admit that the potential consequences of creating something that can match or go beyond human intelligence frighten me. Even now, scientists are teaching computers how to learn on their own. At some point in the near future, their intelligence may well take off and develop at an ever-increasing speed. Human beings evolve biologically very slowly and we would be quickly substituted. In the short term, there is the danger that robots will take over millions of human jobs, creating a large underclass of unemployed people. This could mean large-scale poverty and social unrest. In the long term machines might decide the world would be better without humans.

    Scientist C: I'm a member of the Campaign to Stop Killer Robots. Forget the movie image of a terrifying Terminator stamping on human skulls and think of what's happening right now: military machines like drones, gun turrets and sentry robots are already being used to kill with very little human input. The next step will be autonomous “murderbots” following orders but finally deciding who to kill on their own. It seems clear to me that this would be extremely dangerous for humans. We need to be very cautious indeed about what we ask machines to do.

    Sixteen years ago, I learned an important life lesson in the back of a New York City taxi.

    I was on my way to Grand Central Station, and we were driving in the right lane when a black car suddenly sped out of a parking space right in front of us.

    My driver fit the brakes hard, skidded, and missed the other car by a few inches. The driver of the other car, the man who had just nearly caused a huge accident, started shouting at us. My taxi driver just smiled and waved at him. He was really friendly!

    “Why did you just do that?” I asked him. “This guy almost destroyed your car and could have sent us to the hospital!”

    This was when my taxi driver told me what I now call “the Law of Garbage Trucks”.

    “Many people are like garbage trucks. They run around full of garbage, full of anger, and full of disappointment,” he said. “As their garbage piles up, they need a place to dump it, and if you let them do, they'll dump it on you. So when someone wants to dump on you, just smile, wave, wish them will, and move on. You'll be happier because of what you have done.”

    I started thinking, how often do I let Garbage Trucks run right over me? And how often do I take their garbage and dump it on other people—at work, at home, or on the street? It was on that day that I said, “I'm not going to dump anymore.”

    Sure it's good to get along with your teacher because it makes the time you spend in the classroom more pleasant.

    And yes, it's good to get along with your teacher because in general it's smart to learn how to understand the different types of people you'll meet throughout your life.

    "But really there's one super-important reason why you should get along with your teacher. When you do learning bursts right open " says Evelyn Vuko a longtime teacher who writes an education column(专栏) called "Teacher Says" for the Washington Post newspaper.

    In fact, kids, who get along with their teachers not only learn more but they're more comfortable asking questions and getting extra help. This makes it easier to understand new material and do your best on tests. When you have this kind of relationship with a teacher he or she can be someone to turn to with problems such as problems with learning or school life such as bullying.

    As a kid in a primary or middle school you're at a wonderful stage in your life. You're like a sponge (海绵) able to absorb lots of new and exciting information. On top of that you're able to think about all this information in new ways. Your teacher knows that in most cases is very excited to be the person who's giving you all that material and helping you make it. Remember teachers are people too and they feel great if you're open to what they're teaching you. That's why they wanted to be teachers in the first place-to teach!

    Some kids may be able to learn in any situation whether they like the teacher or not. But most kids are sensitive to the way they get along with the teacher and if things aren't going well they won't learn as well and won't enjoy being in class.