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.

    The Silk Road is a name given to the many trade routes that connected Europe and the Mediterranean（地中海）with the Asian world. The route is over 6,500 km long and got its name because the early Chinese traded silk along it. Although silk was the main trading item, there were many other goods that travelled along the Silk Road between Eastern Asia and Europe. In the course of time, medicine, perfumes, spices and livestock（家畜）found their way between continents.

    The Chinese learned to make silk thousands of years ago. For a long time they were the only ones who knew how to make this precious material. Only the emperor, his family and his highest advisers were allowed to wear clothes made of silk. For a long time the Chinese guarded this secret very carefully. The ancient Romans were the first Europeans who became aware of this wonderful material. Trading started, often with Indians as middlemen（中间人）who traded silk with the Chinese in exchange for gold and silver which they got from the Romans.

    Travelling along the route was dangerous. The hot desert, high mountains and sandstorms made traveling a rough business. Most of the goods along the Silk Road were carried by caravans（商队）. Traders sometimes brought goods from one destination on the silk Road to another, from where the goods would be transported by someone else. Over the centuries people settled along the ancient route and many cities emerged. Later on there were fewer hardships to overcome, but by no means was it easy.

    Religion, languages and diseases also spread along the Silk Road. Buddhism, which originated in India, spread to China along this route. European traders probably brought the plague from Asia to Europe along the ancient road.

    In the early Middle Ages, traffic along the route decreased because of the decline of the Roman Empire. Trading along the Silk Road became stronger again between the 13th and 14th centuries, when the Mongols controlled central Asia. During the Age of Exploration the Silk Road lost its importance because new sea routes to Asia were discovered.

    Mom noticed that something was wrong when I started getting so thirsty. I'd have a lot to drink before bed, which was unusual for me. One time, I opened a big container of apple juice and kept refilling my glass. Before I knew it, I'd drunk the entire container! My mom called my doctor. I then had a few blood tests, and the results were certain — I had diabetes (糖尿病), which meant that the amount of sugar in my blood was very high. That can be dangerous, so I had to learn how to control my blood-sugar level.

    My eating habits had to change in a big way. With diabetes, I can't eat a lot of sugar or carbohydrates (碳水化合物). I have to figure out exactly how much sugar I plan to eat, and then I get an injection of insulin (注射胰岛素) before the meal to help my body process the food. Also, I test my blood-sugar level often. I'm always trying to keep my blood sugar at a healthy level. The level can drop when I exercise, but that doesn't keep me out of gym class or off the basketball court — I just keep some juice boxes around to boost my blood sugar if I need to.

    It's a lot of work and not a lot of fun to keep track of everything, but I've gotten used to my new habits. I was a little scared at first because I wasn't sure how my life would change. Once I knew what I needed to do, though, it wasn't a big deal. My life is different now from what it was before, but it has become completely regular to me.

    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 https: //buy. thetrackr. co/gu/special- offers/15/.

    Imagine a relay race. During this race, an athlete holds a stick as he runs a certain distance. Then he passes the stick to the next runner. That person runs faster, and then passes the stick to a third runner. Now imagine that the runners do not pass a stick. Instead they pass shiny silk, as well as gold, fruit, and glass. Imagine that the race does not move forward in just one direction. Instead the runners go back and forth along a road. They trade goods all along this route (路线) and at each end of it. Now imagine that the runners are businessmen. They lead caravans (商队) or lines of camels that carry things to sell. They travel on the ancient Silk Road to earn their living.

    The Silk Road was a complex trade network. It passed through thousands of cities and towns. It stretched from eastern China, across central Asia and the Middle east, to the Mediterranean Sea. Businessmen traveled on the Silk Road from about 200 B.C. to about 1300 A.D. Then sea travel began to offer new routes. Some people called the Silk Road the world's longest highway. However, the Silk Road included many routes--not just one smooth path. The routes ran through mountains and across deserts. They passed through an area that now includes 18 countries. The Silk Road had many dangers. These dangers ranged from hot sun and deep snow to thieves and wars. Only expert traders could survive.

    The Silk Road got its name from its most prized goods. People used silk as money. They could pay taxes or buy goods with it. Traders carried more than just silk, though. They had gold, silver, and glass from Europe. People in the Middle East and Asia wanted these things. Businessmen also took horses from flat, grassy areas in central Asia and brought them to China and other areas. The horses changed the way people farmed and ran their armies. Indian businessmen traded salt and rare, beautiful stones. Chinese merchants traded medicine and china. They also traded paper, which quickly replaced animal skins in the west. Businessmen carried apples from central Asia to Rome. The Chinese had learned to combine different trees to create new kinds of fruit. They taught this science to others, such as the Romans. The Romans began to grow apples for food. The Silk Road led to worldwide commerce 2,000 years before the World Wide Web.

    The people along the Silk Road did not share only goods. They also shared beliefs. Monks, priests, and other faith leaders taught their religions to others. The Silk Road created pathways for knowledge, diplomacy, and religion.

New archaeological discovers suggest that trade between Europe and Asia along the Silk Road probably began in some form many centuries earlier than once thought. The findings, coupled with a widening range of scientific and historical research, could add a fascinating new page to the epic of the Silk Road.

The latest and most surprising discovery is pieces of silk found in the hair of an Egyptian mummy from about 1000 BC, long before regular traffic on the Silk Road and at least one thousand years before silk was previously thought to be used in Egypt. Other research may extend human activity along this route back even further, perhaps a million years to the migration of human ancestors into eastern Asia.

The official origin of East-West commerce along the road is usually placed in the late 2^nd century BC when an agent of the Chinese Emperor Wu-di returned from a dangerous secret mission across the western desert into the remote high country of Central Asia. The agent, Zhang Qian, travelled as far as Afghanistan and brought back knowledge of even more distant lands such as Persia, Syria and a place known as Lijien, perhaps Rome. Historians have called this one of the most important journeys in ancient times. His journey opened the way for what have been thought to be the first indirect contacts between the ancient world's two superpowers, China and Rome. Chinese silk, first traded to central Asian tribes for war horses and to the Parthians of old Persia in exchange for acrobats and ostrich eggs, was soon finding its way through a network of merchants to the luxury markets of Rome.

But the new discoveries show that Chinese silk was apparently present in the West long before the Han emperor started organized trade over the Silk Road. The research could change thinking about the early history of world trade and provide insights into the mystery of just how and when Europe and the Mediterranean lands first became aware of the glorious culture at the other end of Eurasia.