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    You may like chewing gum (口香糖) after meals to stop your breath smelling bad; or your mother might use a special neutralizer (调理剂) to protect her permed hair (烫发). But have you thought about the chemical principles behind such everyday actions?

    On March 2, the Senior 3 students from the IB (International Baccalaureate, 国际文凭) classes at Beijing Huijia Private School presented their discoveries, all in fluent English. This kind of seminar is held every year to show the achievements of the IB chemistry experiment lessons offered by the school. IB is a qualification based on a common curriculum (课程) for students aged 16-18 in any country and is recognized by universities everywhere.

    "Once I saw an advertisement for xylitol (木糖醇) gum," recalled Zhang Xinju. "Suddenly an idea came to my mind: are there any chemical reactions when the xylitol is working on our teeth?"

    Zhang and his partner Bu Xuan visited several hospitals to try and find out. "Doctors know that xylitol can protect teeth, but few could explain how the chemical reactions happen," said the 17-year-old boy.

    Presenting the results of their research in English to an audience of Chinese and foreign judges was never a problem for the students.

    "Textbooks for IB students are in English, and our teachers speak in English," explained Wei Duan and Han Yu, whose research topic was "The Acid-Base Reaction (酸碱反应) in the process of Hair-Perming".

    "In Senior 1 we often referred to Chinese textbooks, but we found we could understand and express it all in English by the second year."

    Lu Jiang, the school's IB chemistry teacher and China's only IB vice-examiner, is proud that her students can apply scientific theories they learn in class to daily life.

    "You might have learned these facts from you kindergarten teachers, but few think about the theories behind them," Lu said. "This kind of practice is intended to develop the scientific thinking they will need in their future studies."

    When I was a boy there were no smart phones, and our television only got one channel clearly. Still, I never felt bored. The fields, hills and woodlands around my home were the perfect playground whose adventures were only limited by my imagination. I can remember once hiking to nearby lake and walking slowly around it. At the back of it I was amazed to find an old dirt road that I had never seen before. It was full of muddy type tracks and deep woods bordered it on both sides, but exploring it still seemed like a fine adventure.

    I walked on and on for what seemed like hours. I was sure my guardian angel was whispering in my ears "turn around and head back home", but I was stubborn and walked on. There was still neither a car nor a house in sight I noticed that the sun was starting to go down and I grew scared I didn't want to end up trapped on this road, and I was worried that it would be dark before I could make my way back to the lake again.

    I continued to walk on with something growing inside of me. My heart was pounding and my legs were aching. I was almost in tears when I saw something in the distance. It was a house that I recognized. I jumped up and down and laughed out loud. It was still over a mile away, but my legs felt like feathers and I hurried back to my house in no time. I walked in with a big smile on my face just in time for dinner. Then I ended my adventure with a good night's sleep.

    I often thought of that experience recently. Actually, in our life, all roads, no matter how they twist and turn, can lead us home again. They can lead us to our homes in our hearts. May you always walk your path with love! May you always help your fellow travelers along the way! And may your roads always lead you home again!

    I've been researching my family tree since 1998 ，and I've long been curious about DNA as a way to learn more about my roots. The technology has come a long way in the last decade, and it's become more affordable too. Finally, I went ahead and ordered a Y-DNA test.

    The results came in my email inbox from the DNA lab! When I logged in to see the results, there are 29 living people today with whom I share a common direct male ancestor in about the last 1,000 years. They live in Ireland, England, Scotland, South Africa, the United States and probably elsewhere.

    I had two close matches, and the rest were more distant. They both live in Ireland! What makes the connection  to these two men so interesting is that most Irish genealogical (族谱的)records were burned in fires in Dublin and don't exist today. Without them, it's hard to trace Irish roots any further back than the 1800s. I've written emails to both of them and hope to hear back!

    I did some more research on my Y-DNA and found my direct male ancestors were Celtics. They seem to have lived in Western Europe at the time of Ancient Rome. Migration patterns show that my DNA group likely originated in Western Asia, living there 20, 000 and 30, 000 years ago. There are relatives with similar DNA going thousands of years back in what is now Iran, India, Syria, Israel and Turkey.

    I was so excited by these results that I decided to trace my motherly line too. My DNA is already at the lab, so now I just have to wait another month or so, and I'm sure to find more interesting things.

    Life affects friendships. As we grow, marry, fight in wars, move across the country or change jobs, old friendships fall away and new ones form. As long as we live, the things around us change, and as long as things change, friendships are affected.

    When we were children, we had best friends. No matter what happened we were still friends. We live our lives, however, and do what life calls for us to do, and as we got older, memories fade, faces blur(变得模糊),and even friend's names from childhood are forgotten.

    Do you have a question about friendship? Do you wonder what to do with a friend who is no longer friendly? Perhaps you will see that you can't control others. If someone wants to be your friend, it is their choice. All you can do is treat them well and do the best for them when you are with them. Then you wish them well when they leave.

    You can talk to old timers and they will tell you that life is full of incredible(令人难以置信的)joy and incredible sorrow, and that what bothers you today will one day becomes a memory and the pain will be gone. Seniors might tell you that you will learn more as you get older. They will tell you that friendships come and friendships go. Sometimes when they go it will hurt, but you will be okay with it. It's the way life works, after all.

Dear Editor,

    I am writing to you about the article in your magazine last month about youth crime. As a teenager myself I found the article rather offensive(冒犯的) as it suggested that the largest part of teenagers get into trouble with the police at some time or another. I can honestly say that I have never committed a crime(犯罪) and as far as I know, neither have any of my friends.

    I don't know where the journalist got his information from or if he did any proper research, but the way he described teenagers gave me the impression that he doesn't actually know many teenagers. Maybe when he was younger he was regularly in trouble with the police and that's where he got his ideas from. If this is true then he shouldn't judge other people from his own behaviour in the past.

    Many teenagers I know always help other people in the community, such as raising money for charity and doing voluntary work. A group of us recently spent an entire Sunday morning picking up litter in our local park. We didn't get paid for it; we just wanted to make it cleaner and safer for everyone, especially as many young children and dog walkers use the park.

    Also, as teenagers, we are far too busy studying for exams and doing homework to be "walking the streets every night, looking for trouble", as your journalist wrote in his article. I have to study after school every night during the week. I do get some free time at the weekend but I like to play football, go cycling or swimming, go to the cinema or have coffee with my friends and have a chance to talk to them. I think you will agree that there is nothing criminal about that.

    As your magazine is aimed at young readers, I think your journalists should be more careful about what they write and they should research their ideas better, or you may find that teenagers stop buying your magazine altogether.

Yours sincerely,

Daniel Browning

    As free as they make us, mobile phones still need to stay close to a power source. Soon that may change with "green" power.

    Three Chilean students got the idea for a plant-powered device(装置) to charge（使……充电） their cellphones, while sitting in their school's outdoor courtyard during a break from exams, with dead mobile phones. Then, one of them had an "aha" moment.

    “It occurred to Camila to say about plants,” said inventor Evelyn Aravena. “'Why don't you have a socket, if there are so many plants? 'After that, we thought, 'why don't they have a charging outlet（插座）? Because there are so many plants and living things that have the potential to produce energy, why not?'”

    Their invention—a small biological circuit called E-Kaia—uses the energy plants to produce during photosynthesis(光合作用). A plant uses only a small part of that energy and the rest goes into the soil, and that's where the E-Kaia collects it. The device plugs into the ground and then into your phone.

    "It's the most amazing project I've ever seen in my life, plain and simple. They brought this original model, and it worked — and that's when it all changed, at least from my personal point of view and I began to support them." said Mauricio Cifuentes.

    The device solved two problems for the engineering students — they needed an idea for a class project, and an outlet to plug in their phones.

    "Looking for a place to charge the notebook, which had no power, and the mobile phones, we weren't able to find anything because all the other students were in the same state of madness trying to find a place to charge their devices," said Aravena.

    But plants are everywhere, and the bio－circuit makes good use of their excess(过多的) power.

    The E-Kaia doesn't carry much charge but it's powerful enough to completely recharge a mobile phone in less than two hours.

    The student inventors have applied for patents（专利） on their technology, and expect the E-Kaia to go on sale in the near future.