Sometimes, you just can't help it. Maybe you're watching a sad movie, or thinking about the friend who moved away. Next thing you know, your eyes are watering, and you havetears running down your cheeks. Why do peoplecry when they are emotional? What are tears? Scientists are working hard to find the answers to these questions.

    Ad Vingerhoets is a professor of psychology at Tilburg University, in the Netherlands. He is one ofthe few scientists in the world who have studied crying. According to Vingerhoets, there are three types of tears. Basal tearsare the first type. Theylubricate(润滑) the eyes andact as a protective barrier between the eye and the rest of the World. Next arereflex tears. They wash youreyes clean when something gets in them. Finally, there are emotional tears. “These are released in response to emotional states, ”explains Vingerhoets. “Especially when we feel helpless.”

    Scientists believe that crying has something to do with how humans developed and learned to depend on each other.“Humans are very complex social creatures,”says Lauren Bylsma, a professor at the University of Pittsburgh, in Pennsylvania.“It seems that tears serve to arouse help and support from others," She says. “Another reason we weep is that humans have the longest developmental period of almost any animal. It takes along time to grow up. ”

    Vingerhoets agrees. “I think that the reason why humans shed tears(流眼泪) has somethingto do with our childhood,”he says. “That's the time when we are stir dependent on adults for love and protection and care. The major advantage of emotional tears is that you can target them at a specific person.”Vingerhoets says this ability to target someone could have come in hand in prehistorictimes, when humans were living among dangerous animals. Crying couldattract predators(捕食者). Tears were asafer way to get attention. In this case, it is better to use a silent signal to ask for help,”he says.

    Vingerhoets and Bylsma do frequent studies to better understand why humans cry. According to Byhma, there is still much more to discover. “It's surprising,”she says,“how much we still don't know.”

    LONDON—Terror struck in the heart of London on Thursday as explosions ripped through three subway trains and blasted(炸开)the roof off a crowded red double-decker bus. At least 37 people were killed and more than 700 wounded in the deadliest attack on the city since the blitz(闪电战)in World War II.

British Prime Minister Tony Blair blamed Islamic extremists and said the bombings were designed to coincide with the opening in Scotland of a G-8 summit of the world's most powerful leaders. Foreign Secretary Jack Straw said the bombings—which came the day after London won the bid to host the 2012 Olympics— have the “hallmarks(特点)of an al-Qaida-related attack”.

    Trapped passengers in the Underground railway threw themselves on the floor, some sobbing. As subway cars quickly filled with smoke, people used their umbrellas try to break the windows so that they could get air. Passengers emerged from the Underground covered with blood and soot(黑烟). On the street, in a light rain, buses ferried the wounded, and doctors used a hotel as a hospital.

     “I didn't hear anything, just a flash of light, people screaming, no thoughts of what it was. I just had to get out of the train,” said subway passenger Chris Randall, 28, who was hospitalized with cuts and burns to the face, the legs and hands.

     “It was chaos(混乱),” said Gary Lewis, 32, evacuated(撤离)from a subway train at King's Cross station. “The one haunting(萦绕)image was someone whose face was totally black( with soot) and pouring with blood.”

    Police said there had been no warning and that the blasts at three subway stations went off within 26 minutes, starting at 8:51 a.m. in an Underground train just outside the financial district. Authorities initially blames a power failure but realized it was a terror attack after the bus bombing near the British Museum at 9:47 a.m.—less than an hour after the first explosion.

    Shopping is a big part of the holiday season,when families and friends gather together and exchange gifts.While the popularity of shopping online has grown,such practices are not always eco-friendly or timely,as gifts bought online must be packaged and shipped,wasting valuable resources and time.

    The benefits of shopping locally go beyond convenience and reduce your carbon footprint.The following are a few ways that shopping locally this holiday season can directly benefit your community and the people who call it home.

    When men and women shop locally,they are putting money back into their local communities.Local businesses may be owned by your neighbors,and it can be comforting to know that your holiday shopping dollars are going to support a neighbor instead of a large company.Local businesses also employ your neighbors,so shopping locally can strengthen the local economy by creating jobs.

    Local businesses go a long way toward creating a neighborhood identity,and that identity can create a stronger sense of community among you and your neighbors.In addition,a unique community    identity can make your town more attractive to outsiders,and can also attract more people to local businesses in your neighborhood.

    The gifts you buy when shopping locally can also benefit your community.Gifts purchased from small local businesses tend to be more unique than items bought from national chains,as smaller retailers tend to sell more home-made items than their national competitors.Recipients of such items may find such gifts more thoughtful than mass produced items bought from national chains.

    The accessibility of customer service is another benefit of shopping locally.When you buy something from national chains,especially during the holiday season when such businesses may have to deal with orders,making contact with customer service departments can be a test of patience.A long wait on the phone or online can make the process of contacting customer service departments extremely frustrating.But such frustration is rare when shopping from local businesses,as consumers can simply buy their products in the store.In addition,shopping locally makes it more convenient for friends and family members who also live in your community to return their gifts.

    "You're going to do WHAT?" I asked my best friend, Julie, in alarm.

    "I'm going to try out for the cheerleading squad (啦啦队)," she said, eyes fixed on the ground. We had been best friends since second grade and we did everything together. We had made many plans about what we would do this year, but now she was going off on her own. I was sure that if she joined the cheerleading squad, she would become best friends with someone else and I couldn't stand the thought.

    "Why are you doing this? Do you really want to hang around with those girls instead of me?" I cried, my voice filled with anger.

    "It's not about the girls," Julie said. "It's about the sport. I want to be on the squad at the high school level because they win scholarships (奖学金) at state competitions, and I have a better chance if I'm on the squad here," she explained. "Besides," she added, "it's not like I'm leaving the country or something."

    "Goodbye," I marched off, leaving Julie standing with a sad look on her face.

The rest of that week I was unhappy, and I avoided Julie in the hall. I planned to watch the first game and ignore Julie. Instead, I was amazed by the enthusiasm and skill of Julie's cheering. Although she was the youngest member of the team, Julie enthusiastically led cheer after cheer. I saw how her face lit up with joy. I was stunned (目瞪口呆) as I realized that she loved the sport. Trying out for the team had nothing to do with me—maybe it was just something she wanted to do.

    I approached her shyly, but Julie smiled immediately. "Hey, you were really great." I began, and then added quickly, "I'm so sorry I've been rude to you about your joining the squad."

    Julie smiled and replied, "A group of us are going for ice cream. Why don't you come along?"

    Julie's quick forgiveness made my eyes burn, but I smiled in return. As I walked toward the cheerleaders, I realized there was room in Julie's life for all of us. We could save the competition for the game.

    Eco-friendly Vauban, lied in the southwest part of Germany, has everything－tree-lined streets, perfect houses－but it's missing one urban feature of the last 100 years or so: the car. And Vauban residents(居民) don't mind one bit. Vauban doesn't ban cars entirely. Rather, it just tries to reduce the use of cars by creating “parking-free” and “car-free” living. In Vauban, parking spots are a no-no private property(私人财产). Cars can only be parked in public parking lots, so living without a car saves residents the cost of parking in the public lot. Cars also are prevented from using certain roads and must stick to strict speed limits. With these limitations, fewer than 20 percent of residents own cars. Without cars, bikes are almost religion in this small town. Kids pick them up even before they can ride one. Vauban is about much more than just using two wheels instead of four. In Vauban , residents ride bikes and even receive money from the electric company for selling electricity back to the power grid (电网系统). It's an environmentally-friendly city of the future, with organically grown food, renewable energy, and carbon-neutral homes. And now, with a population of 5,500, it's attracting attention from around the world. Can an eco-friendly city like Vauban be a model for Americans to stop their over-reliance on the cars?

    Sometimes when I watch a news report what's in the back of my mind is what isn't being reported or stressed. While this eco-friendly city is inspiring in that it shows residents getting exercise and fresh air through the majority use of bicycles, as well as good old fashioned walking, common sense would tell you that even for a place like Vauban, Germany, it owes its existence to the cars.

    Do you think that bicycles were able to transport all the construction materials that were needed to build and maintain the eco-friendly homes and businesses in Vauban? It took cars to help build this utopia. It's one of the paradoxes of life that sometimes in order to get away from relying on something like the car, you actually have to rely on that very thing at the beginning and into the foreseeable future to some degree.

    I myself haven't owned a car for more than 14 years, and mostly get around town running, walking, or using public transportation. There are times I wish I had one, since it would make many things easier, but overall I'm glad not to have to deal with the headaches of owning a car, which caused me to get rid of it in the first place. And all the walking and running has helped to keep me fit and healthy.

    To get even close to being like eco-friendly Vauban, Americans will need to absolutely change the way they live. Commuting(乘车上下班) patterns will have to change, public transportation will have to be invested in, and so on. And though ending our love affair with the car will be impossible during my lifetime, we may at least start to see more Vauban-like areas in the USA.

    We can hope that Americans will consider using their feet more to get around, cutting down on pollution, and giving themselves some more exercise.

Max Mathews has been called the father of computer music.He created electronic tools so that people could use computers as musical instruments.He had a great influence on the development of electronic music and how it is written,recorded and played.

In 1957,Mathews wrote the first computer program that enabled a computer to create sound.At that time,he was working as an engineer at Bell Laboratories in New Jersey.His computer program enabled a large IBM computer to play a 17 seconds piece of music that he had written.The computer was so slow that it would have taken an hour to play the piece of music in 17 seconds.For that reason,Mathews moved the work to a tape player,which could be sped up to play the music at a normal speed.He later said that the sound quality of the musical notes was not great,but the technical importance of the music was huge.

Mathews continued creating other versions of the music program.He became interested in how computers could help musicians outside recording studios.The Groove program he developed was the first computer program made for live performances.

He also developed an electronic device he called the Radio Baton.The device looks like two drum sticks.It enables the user to control the speed and sound levels of orchestral music playing on a computer.The user does this by moving the two sticks on a special electronic surface.

Mathews believed modern musicians are not making full use of the power of computer music.He said a violin always sounds like a violin.But with a computer,the way a violin sounds is unlimited.He said he didn't want computer sounds to replace live music.But he said he hoped laptop computers would one day be considered serious instruments.