When a leafy plant is under attack ，it doesn't sit quietly. Back in 1983, two scientists, Jack Schultz and Ian Baldwin,reported that young maple trees getting bitten by insects send out a particular smell that neighboring plants can get. These chemicals come from the injured parts of the plant and seem to be an alarm.What the plants pump through the air is a mixture of chemicals known as volatile organic compounds,VOCs for short.

Scientists have found that all kinds of plants give out VOCs when being attacked .It's a plant's way of crying out.But is anyone listening?Apparently.Because we can watch the neighbours react.

    Some plants pump out smelly chemicals to keep insects away.But others do double duty .They pump out perfumes designed to attract different insects who are natural enemies to the attackers. Once they arrive, the tables are turned. The attacker who was lunching now becomes lunch.

    In study after study,it appears that these chemical conversations help the neighbors .The damage is usually more serious on the first plant,but the neighbors ,relatively speaking ,stay safer because they heard the alarm and knew what to do.

Does this mean that plants talk to each other? Scientists don't know. Maybe the first plant just made a cry of pain or was sending a message to its own branches, and so, in effect, was talking to itself. Perhaps the neighbors just happened to “overhear” the cry. So information was exchanged, but it wasn't a true, intentional back and forth.

    Charles Darwin, over 150 years ago, imagined a world far busier, noisier and more intimate(亲密的) than the world we can see and hear. Our senses are weak. There's a whole lot going on.

    Our room was on the second floor but you could still hear the roar of the ocean and see the stars at night. I used to take long walks along the water. The food in town was wonderful and the people were very friendly. The area was very quiet and peaceful, and fairly deserted.

    The last evening of our vacation, however, we all heard strange footsteps following closely behind us as we were walking up to our room in the holiday centre. We turned around and noticed a fairly young man moving very rapidly across the beach and getting closer to us. He was tall and wore a baseball cap. We didn't have any cell phones on us. I never saw Dad as worried as he was then and knew that something was terribly wrong. The sense of fear started to overwhelm Mom and me. We had had such a good time in town. Now, the night was rapidly turning into a dangerous situation.

    We could hear the man's footsteps getting closer. Dad's face was almost pale. The so-called intruder (侵入者) had moved nearer and nearer when all of a sudden, the nearby vending (自动贩卖) machine started going crazy and spitting out cans of soda! The noise actually scared the intruder and he ran out of sight. My parents were shaking, but we all turned around to see who had put money into the vending machine downstairs, and actually saved us, but no one was around at all.Not a soul.

    It's one vacation I will never forget.

    Technology is the application of knowledge to production. Thanks to modern technology, we have been able to increase greatly the efficiency of our work force. New machines and new methods have helped cut down time and expense while increasing overall output. This has meant more production and a higher standard of living. For most of us in America, modern technology is thought of as the reason why we can have cars and television sets. However, technology has also increased the amount of food available to us, by means of modern farming machinery and animal breeding techniques, and has made our life span longer via medical technology.

    Will mankind continue to live longer and have a higher quality of life? In large measure, the answer depends on technology and our ability to use it widely. If we keep making progress as we have over the past fifty years, the answer is definitely yes. The advancement of technology depends on research and development, and the latest surveys show that the united States is continuing to put billions of dollars annually(每年) into such efforts. So while we are running out of some limited resources, we may well find technological substitutes (代用品) for many of them through our research programs.

    Therefore, in the final analysis, the three major factors of production (land, labor and capital) are all influenced by technology. When we need new skills or techniques in medicine, people will start developing new technology to meet those needs. As equipment proves to be slow or inefficient, new machines will be invented. Technology responds to our needs in helping us improve our standard of living.

    A recent study by Citi Retail Services found that a growing number of people are embracing digital wallets or e-wallets, due in large part to their convenience and ease of use.

    E-wallets have been called the future of real-world payment technology.With major players like Alipay,WeChat and Apple Pay becoming popular,it seems to be a safe bet that a change in consumer payment technology is coming soon.

    CNN reporter Paul Ripley experienced a day in Beijing without his wallet."In China's largest cities, you can definitely survive without carrying a pocket full of cash and credit cards-as long as you've got your smartphone."He paid for breakfast by scanning a QR code on the window of a hole-in-the-wall restaurant.All he had to do was to enter a password and the transaction was complete.

    Unlike the situations in the US and other countries,"China doesn't have a really money-making credit card system, so Chinese people just skipped credit cards and went straight to mobile payments."Gu Yu,co-founder of the new payment app Mileslife,told CNN.He also pointed out the advantages of mobile payments."No coins or bills that can be lost or stolen. electronic receipts, the ease of keeping rack of spending-and of course,no wallet taking up space."he said.

    However, if we want to make e-wallets a mainstream trend a lot of things will have to change over the coming years.Perhaps one of the most important things that need to be changed is how people regard e-wallets.Linda Barrabee,research director for NPD Connected Intelligence, said in a statement."In order to promote on-the-go consumer transactions and commerce, wireless carriers, credit card companies, and e-commerce companies need to make sure the process is convenient,simple,and secure for consumers."

    On my first day of high school, going into math class, I was pointed and laughed at by two of my classmates. I initially thought my fly was open, or that something was stuck in my teeth. But as I took my seat, I heard one student whisper, "Why is a black boy taking Honors?" So, my fly wasn't open. An honors level class had simply been taken by a student whose skin was brown.

    Many people think my clothes should be big enough for me to live in, or expect me to listen to only "black music." In seventh grade, a group of my classmates fixed their cold stares on my clothes. They called out to me, "Go get your gangsta clothes." In one of my Spanish classes, the teacher asked me, "Do you like rap music or rock music more?" I replied, "Rock." The look of shock on my classmates' faces made me uncomfortable.

    Now I still take all Honors courses. I still wear clothes that fit me. My music library covers from rock to pop to techno, and almost everything in between. When it comes to choosing my friends, I am still colorblind. I continue to do my best to work in school in order to reach my goals; and yet, when I look in the mirror, I still see skin of that same brown.

    I believe in being myself. I believe that I myself should decide who I am and what actions I take in life. In high school, popularity often depends on your willingness to follow trends. And I've been told that it doesn't get much easier going into adulthood. But the only other option is to sacrifice my personality for the satisfaction and approval of others. This can be appealing, but I'm not going to do that.

    More and more travellers in China nowadays prefer homestays rather than traditional hotels, as they seek private living experiences. The house-sharing model was first introduced by the website Couchsurfing, com in 2003. It is still the largest website for travellers to find accommodation(住宿) without much money to spend.

    Encouraged by her great experience of homestays in France, Maggita, 30, considered short-term hire as her first choice in her future trips. She later went back to her hometown Shanghai and ran a "shared accommodation" business.

    The short-term hire idea has been a win-win business model. For travellers, they can rent a special room at a reasonable price and also enjoy a firsthand experience of the local culture, compared with traditional hotels. For owners, they can gain much with daily rental. Now Maggita has quit her last job in an IT company and become a host of some 20 homestays, which enables her to earn a monthly income of around 40,000 —50,000 yuan.

    In recent years, China has seen many homestay booking websites such as Xiaozhu and Tujia. Chen Chi, the founder and CEO of Xiaozhu, said the model is to share rooms or apartments that are not in use with people who need them. Instead of the traditional view that Chinese people feel uncomfortable living with strangers, Chen found that a large number of travellers got along well with house owners.

    However, experts have pointed out a series of problems brought about by the fashion. Lacking supervision(监管) to those accommodation sharing websites, the service quality and accommodation safety cannot be guaranteed(保障).Experts suggest that the online websites should closely work together with communities and local police stations to improve the services.