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.

    You have to shake hands when you're coming or going in Germany, but in Britain you usually only shake hands when you meet someone for the first time.

    You have to give your present in public in the Middle East to show it's not a bribe(贿赂), but it's good manners to give your present in private in Asia.

    You mustn't give cutlery（刀具） in Latin America because it suggests that you want to cut off the relationship. You mustn't give a clock in China because the Chinese word for clock is similar to the word for funeral(葬礼).

    “Come any time” means “I want you to visit me” in India. If you don't suggest a time and arrange a visit immediately, an Indian will think you are refusing the invitation.

    Offices are usually closed on Friday in Moslem countries.

    It's bad manners to discuss business at social occasion in India.

    In an English pub, you have to take your turn to buy a “round” drink for everyone in your group.

    America is a mobile society. Friendships between Americans can be close and real, yet disappear soon if situations change. Neither side feels hurt by this. Both may exchange Christmas greetings for a year or two, perhaps a few letters for a while — then no more. If the same two people meet again by chance, even years later, they pick up the friendship. This can be quite difficult for us Chinese to understand, because friendships between us flower more slowly but then may become lifelong feelings, extending (延伸) sometimes deeply into both families.

    Americans are ready to receive us foreigners at their homes, share their holidays, and their home life. They will enjoy welcoming us and be pleased if we accept their hospitality (好客) easily.

    Another difficult point for us Chinese to understand Americans is that although they include us warmly in their personal everyday lives, they don't show their politeness to us if it requires a great deal of time. This is usually the opposite of the practice in our country where we may be generous with our time. Sometimes, we, as hosts, will appear at airports even in the middle of the night to meet a friend. We may take days off to act as guides to our foreign friends. The Americans, however, express their welcome usually at homes, but truly can not manage the time to do a great deal with a visitor outside their daily routine. They will probably expect us to get ourselves from the airport to our own hotel by bus. And they expect that we will phone them from there. Once we arrive at their homes, the welcome will be full, warm and real. We will find ourselves treated hospitably.

    For the Americans, it is often considered more friendly to invite a friend to their homes than to go to restaurants, except for purely business matters. So accept their hospitality at home!

    A student is learning to speak British English. He wonders: Can I communicate with Americans? Can they understand me? Learners of English often ask: What are the differences between British and American English? How important are these differences?

    Certainly! There are some differences between British and American English. There are a few differences in grammar. For example, speakers of British English say “in hospital” and “Have you a pen?” Americans say “in the hospital!” and “Do you have a pen?”. Pronunciation is sometimes different. Americans usually sound theirs in words like “bird” and “hurt”. Speakers of British English do not sound theirs in these words. There are differences between British and American English in spelling and vocabulary. For example, “color” and “honor” are British, “color” and honor” are American.

    These differences in grammar, pronunciation, spelling and vocabulary are not important, however. For the most part, British and American English are the same language.

    Feifei, an 11-year-old boy from Xuzhou, Jiangsu Province, suffered from a sudden acute eye disease which has almost led to blindness. The disease was caused by excessive(过度的)eye fatigue(疲劳)during the winter vacation, during which he played computer games for continuous 10 days and nights.

    Many youngsters in China nowadays are increasingly addicted to computer games and other electronic products. This is followed by a series of health problems, with the most typical case being myopia, or nearsightedness.

    According to the latest research report released by the World Health Organization (WHO), the myopia   rate among Chinese teenagers ranks first in the world—70 percent of high school and college students. The rate is nearly 40 percent in primary school students, while it is only 10 percent for their peers in the United States.

    There are at least 10 million people in China with severe myopia, and they are likely to get pathological(病理性的)myopia in middle age. Pathological myopia can't be treated with glasses or surgery, and it is one of the biggest factors that lead to blindness, Xu Xun, director of the ophthalmology(眼科学) department at Shanghai General Hospital, pointed out.

    Experts explain that two major factors lead to the high rate of myopia among Chinese people. One is high academic pressure, and the other one is excessive use of electronic devices over a long period of time. Genetics, on the other hand, are not the main reason, as only 20 percent of Chinese people had myopia in the 1960s.

    "Teenagers are now faced with severe academic pressure, which means they often study without natural light. This increases their risk of becoming nearsighted," Xu said.

    Experts suggest that youngsters maintain a proper balance between study and rest so as to protect their eyesight, and parents should play an active role in the process.

    Procter & Gamble (P&G), one of the world's biggest marketers, has announced a change in the way it buys advertising on Facebook. It has started cutting its spend on highly targeted ads and increasing its spend on ads that address much larger numbers of the potential audiences for its brands, which include Tide, Pampers and Gillette. Explaining this change of emphasis, P&G's global brand building officer, Marc Pritchard, said, "We targeted too much, and went too narrow."

    Facebook's astonishing income growth comes, in part, from its ability to deliver micro-targeted audiences (推送精准目标受众) to advertisers, and P&G in fact admits that it has wasted millions of dollars in the misguided pursuit of effectiveness.

    Facebook used to be irresistible to advertisers. It presents advertisers this question: Instead of sending your message to millions in a television ad, why not use data to reach only those you need to reach? But as many people may have noticed, making perfectly targeted ads appears to be much harder than it sounds. Most digital ads are easily ignored. Information about consumers is not the same as insight into human beings.

    The more fundamental problem with micro-targeting is that for big brands, advertising has never really been about messages—even brand owners have never quite realized it. It is about the creation of shared memories, triggered at the point of purchase. Think about some of the great brands: Nike, Apple, and yes, Pampers. If you buy them, it is because you know millions of others do, and because they seem to stand for something that, far from being unique to you, is common to all of us: achievement, creativity, and nurturing. The broader these brands go, the better they do.

    When a consumer reaches for something on the shelf, they usually reach for the familiar. To achieve that status, a brand needs to have done something that lots of people regularly see, notice and enjoy. What seemed to be the wastefulness of TV was in fact its secret sauce. By reaching large numbers of people at the same time, TV ads had the power to turn brands into cultural icons, which took up consumers' minds.

    In its conversations with advertisers, Facebook now talks less about targeting, preferring to emphasize the large number of consumers that it can help brands to reach. It is investing in video functions and is encouraging its clients to make short films. After years of telling clients TV is wasteful, it is now doing a good job of imitating it.