Dujiangyan is the oldest man-made water system in the world, and a wonder in the development of Chinese science. Built over 2,200 years ago in what is now Sichuan Province in Southwest China, this amazing engineering achievement is still used today to irrigate over 6,000 square kilometres of farmland, take away floodwater and provide water for 50 cities in the province.

    In ancient times, the region in which Dujiangyan now stands suffered from regular floods caused by overflow from the Minjiang River. To help the victims of the flooding, Li Bing, the region governor, together with his son, decided to find a solution. They studied the problem and discovered that the river most often overflowed when winter snow at the top of the nearby Mount Yulei began to melt as the weather warmed.

    The simplest fix was to build a dam, but this would have ruined the Minjiang River. So instead Li designed a series of channels built at different levels along Mount Yulei that would take away the floodwater while leaving the river flowing naturally. Better still, the extra water could be directed to the dry Chengdu Plain, making it suitable for farming.

    Cutting the channels through the hard rock of Mount Yulei was a remarkable accomplishment as it was done long before the invention gunpowder and explosives. Li Bing found another solution. He used a combination of fire and water to heat and cool the rocks until they cracked and could be removed. After eight years of work, the 20-metre-wide canals had been carved through the mountain.

    Once the system was finished, no more floods occurred and the people were able to live peacefully and affluently. Today, Dujiangyan is admired by scientists from around the world because of one feature. Unlike modern dams where the water is blocked with a huge wall, Dujiangyan still lets water flow through the Minjiang River naturally, enabling ecosystems and fish populations to exist in harmony.

    There have been times in my life when I felt satisfied.Sometimes it was because I achieved a goal I had set. Sometimes it was because I overcame a fear or passed a test.However,every time I feel that way,I learn again that full isn't full.

    When I was a little boy,I felt that the love I had for my mom and dad,and the love they had for me,just filled me up.Surely in a house full of nine people lived a young boy who loved and was loved as fully as a person could stand. Imagine my surprise as I then extended（扩大影响）that love to my grandparents,my uncle & aunt,cousins,etc.As I grew older,I met and married a beautiful woman that I thought entirely filled me up with love.I could not imagine there would be any more room.Then a few short years later we added one daughter and then another daughter to our family.Again,I had room to love and be loved.See what I mean?Every time I feel that life and love are as good as they can get,they get better.

    There is a lesson here for us.We ought to always have a heart that is open to expanding.To do more,love more, live more,learn more,overcome more,forgive more and the list could go on.Each of us knows 100 stories about men and women who have proved the impossible to be possible.Every day we stand at the crossroad and must decide if we are going to be a better person today than we were yesterday.

    You are not full yet.Young or old,there is still room for more.

    You dash through a crowded railway station, tripping over bags, spilling (泼出) your coffee, only to have the doors slide shut in your face, leaving you breathless on the platform as the train pulls away,

    But at least, if you're in France, someone may be playing the piano for you. But it won't be performed by a paid musician, or even a street entertainer playing for coins. It will just be a random passer - by, jamming for the fun of it on one of the pianos that the national railroad company, S. N. C. F., has fixed in nearly 100 stations across France. They are free for anyone to play, and travelers from all walks of life have taken to doing just that.

    Gares & Connexions, the S. N. C. F. division that manages its stations, rents the instruments from the producer, Yamaha: which maintains them and tunes them every month or two. The first one was set up in the Gare Montparnasse in Paris in 2012.

    The music, mixed with the sounds of shouting passengers, screaming trains and rolling suitcases, gives French stations a special soundscape. The amateur musicians have included Irish soccer fans and even babies. In 2014, Gares & Connexions and Yamaha organized a nationwide contest called Your Turn to Play, asking participants to submit videos of themselves using one of the pianos. It drew nearly 900 entries.

    Isn't the railroad company taking a big chance? Apparently not: “None of the instruments has been vandalized to this day, or even merely damaged,” said Claire Foumon, a spokeswoman for Gares & Connexions. “They are shared and respected by all.”

    So if you miss a train in Paris; Bordeaux or Marseille one day, perhaps someone will be playing a favorite piece that will ease your pain. Or perhaps you'll sit down and play your annoyance away yourself.

    Do you believe in the power of music? If you're like most kids these days, you probably have an electronic device loaded with hundreds or even thousands of your favorite songs. At any moment in time, you can fill your headphones with the sounds of a particular song that suits your mood at that exact time.

    Are you getting ready for a big soccer match or do you need to get excited? Maybe some hip hop with a strong beat will do the trick! Besides, you might be ready to study for a big exam the next day. To calm your nerves and help you concentrate, a little bit of Mozart might make memorization more manageable.

    But is there any scientific evidence of these effects that music seems to have? You bet there is! Scientists have long recognized the power of music. Over the years, many studies have been conducted to examine in greater depth the nature and extent of the effects music has on people.

    For example, scientists at the University of Missouri have found that listening to music can have a positive effect on your mood. Their research gives scientific credibility(可信性)to the behavior that many people have already experienced on their own: listening to upbeat music can brighten your day and boost your mood.

    Other studies have shown that upbeat music isn't the only type of music that can be helpful, however. When people are sad or have suffered a personal loss, sad music can be helpful because people identify with the tone and lyrias(歌词)of the music. Likewise, people under a lot of stress or experiencing upsetting situations can benefit from listening to angry music. Although angry music might not help you if you're in a normal mood, its tone can benefit you when you are dealing with stressful and upsetting situations.

    You can relax if remembering everything isn't your strong suit. Recent research makes the case that being forgetful can be a strength—in fact, selective memory can even be a sign of stronger intelligence.

    Traditional research on memory has focused on the advantages of remembering everything. But looking through years of recent memory data, researchers found that the neurobiology of forgetting can be just as important to our decision-making as what our minds choose to remember.

    Making intelligent decisions doesn't mean you need to have all the information at hand. It just means you need to hold onto the most valuable information. And that means clearing up space in your memory palace for the most up-to-date information on clients and situations. Our brains do this by creating new neurons(神经元）in our  hippocampus, which have the power to overwrite(重写)existing memories that are influencing our decision-making.

    If you want to increase the number of new neurons in our brain's learning region, try exercising. Some aerobic exercise like jogging, power walking and swimming has been found to increase the number of neurons making important connections in our brains.

    When we forget the names of certain clients or details about old jobs，the brain is making a choice that these details don't matter. Although too much forgetfulness can be a cause for concern, the occasional lost detail can be a sign of a perfectly healthy memory system. The researchers found that our brains facilitate decision-making by stopping us from focusing too much on unimportant past details. Instead，the brain helps us remember the most important part of a conversation.

    We can get blamed for being absent-minded when we forget past events in perfect detail. These findings show us that total recall(记忆)can be overvalued. Our brains are working smarter when they aim to remember the right stories, not every story.

    Fights at school sometimes happen. But how can you keep away from a fight? Here's something you can do.

    Be calm (冷静). Sometimes, you feel so angry that you really want to teach somebody a lesson. But being angry can't solve problems. Neither can a fight. Instead, it may bring you more problems. In the school, everyone involved (卷入) in a fight will be punished, no matter who started it. There are winners in a fight.

    Shout loudly. If you know someone is coming up behind you to attack, turn toward the person with your hands up in front of your body and loudly say "stop" before walking away. Loud voice can usually make the attacker calm down. If the person doesn't stop, cry for help by calling out the name of a teacher whose office is nearby.

              . Your friend may ask you to join in a fight. Learn to say no. Helping him fight is not really helpful to him. If you really want to give him a hand, try to ask him to give it up. Also, you can tell him if he gets involved in a fight, he may get hurt and be punished. Then, try to learn why he wants a fight and help him find a right way to deal with the problem.