Recently some American scientists have given a useful piece of advice to people in industrialized nations．They say people should eat more of the same kind of food eaten by humans living more than 10,000 years ago． {#blank#}1{#/blank#}

    The scientists say that the human life has changed greatly．Our bodies have not been able to deal with these changes in lifestyle and this had led to new kinds of sicknesses． {#blank#}2{#/blank#} So they are called “diseases of civilization”．Many cancers and diseases of the blood system are examples of such diseases.

    Scientists noted that people in both the Old Stone Age and the New Stone Age enjoyed very little alcohol or tobacco, probably none． {#blank#}3{#/blank#} However, a change in food is one of the main differences between life in ancient times and that of today.

    Stone Age people hunted wild animals for their meat, which had much less fat than domestic ones．They ate a lot of fresh wild vegetables and fruits．They did not have milk or any other dairy products, and they made very little use of grains． {#blank#}4{#/blank#} We eat six times more salt than our ancestors．We eat more sugar．We eat twice as much fat but only one third as much protein and much less vitamin C.

    {#blank#}5{#/blank#} But scientists say that we would be much healthier if we eat much the same way the ancient people did, cutting the amount of fatty, salty and sweet food.

A．Stone Age people lived a simple life.

B．But today, we enjoy eating a lot of these.

C．In that case, they would live much healthier.

D．Ancient people also got lots of physical exercise.

E．These new sicknesses were not known in ancient times.

F．People today probably don't want to live like our ancestors.

G．Modern people used to suffer from “diseases of civilization”.

You might think people all over the United States have Wi-Fi—-wireless Internet service—and mobile phones. But there is no such service in Green Bank, West Virginia, a tiny town four hours from the U.S. capital, Washington D.C. Fewer than 150 people live in Green Bank, which has two churches, an elementary school and a public library. It is also home to the largest radio telescope in the world.

    There is a ban on Wi-Fi in Green Bank, along with anything else that can create electromagnetic(电磁的)waves. Officials say the waves could disturb the signals the telescope receives.

For many American, a visit to Green Bank is a little like returning to the 1950s. To get there, you must read road signs—because there is no GPS service in the town. People can connect with the Internet through telephones, but wireless service is not allowed.

    The observatory(天文台)is one of the largest employers in the area. The federal National Science Foundation(NSF)spends about ﹩8.2 million a year to operate the observatory, telescope and educational center.

    Jonah Bauserman is a technician. If he supposes there is a signal that is not allowed in the zone, he drives to the house where the signal is coming from and checks it. But once a week, when the device is cleaned, some banned devices are allowed near it.

    People in the town respect the work of the scientists. And they say they are happy to live without Wi-Fi and mobile phones. “You know, instead of sitting here on our phones and other devices we're out fishing and hunting and going to each other's houses.” Everyone knows each other and communication is almost always face-to-face.

    We can make mistakes at any age. Some mistakes we make are about money. But most mistakes are about people. Did Jerry really care when I broke up with Helen? When I got that great job, did Jim really feel good about it, as a friend? Or did he envy my luck? And Paul-why didn't pick up that he was friendly just because I had a car? When we look back, doubts like these can make us feel bad. But when we look back, it's too late.

    Why do we go wrong about our friends or our enemies? Sometimes what people say hides their real meaning. And if we don't really listen we miss the feeling behind the words. Suppose someone tells you. You're a lucky dog. That's being friendly. But lucky dog? There's a bit of envy in those words. Maybe he doesn't see it himself. But bringing in the dog bit puts you down a little. What he may be saying is that doesn't think you deserve your luck.

    Just think of all the things you have to be thankful for another noise that says one thing and means another. It could mean that the speaker is trying to get you to see your problem as part of your life as a whole. But is he? Wrapped up in this phrase is the thought that your problem isn't important. It's telling you to think of all the starving people in the world when you haven't got a date for Saturday night.

    How can you tell the real meaning behind someone's words? One way is to take a good look at the person talking. Do his words fit the way he looks? Does what he says agree with the tone of voice? His posture（姿态）? The look in his eyes? Stop and think. The minute you spend thinking about the real meaning of what people to you may save another mistake.

    There is virtue in working standing up. It sounds like a fashion. But it does have a basis in science.

    That, by itself, may not be surprising. Health ministries ask people for decades to do more exercise. What is surprising is that long periods of inactivity are bad regardless of how much time you also spend on officially approved high-impact stuff like pounding treadmills(跑步机) in the gym. What you need instead, the latest research suggests, is constant low-level activity. This can be so low-level that you might not think of it as activity at all. Even just standing up counts, for it invokes muscles that sitting does not.

Researchers in this field trace the history of the idea that standing up is good for you back to 1953, when a study published in The Lancet found that bus conductors, who spent their days standing, had a risk of heart attack half that of bus drivers, who spent their shifts on their backsides. But as the health benefits of exercise and vigorous(强度大的) physical activity began to become clear in the 1970s, says David Dunstan, a researcher at the Baker IDI Heart & Diabetes Institute in Melbourne, Australia, interest in low-intensity activity — like walking and standing — became weaker.

    Over the past few years, however, interest has been excited again. A series of studies, none big enough to provide convincing evidence, but all pointing in the same direction, persuaded Emma Wilmot of the University of Leicester, in Britain, to carry out a meta-analysis. This is a technique that combines diverse studies in a statistically meaningful way. Dr Wilmot combined 18 of them, covering almost 800,000 people and concluded that those individuals who are the least active in their normal daily lives are twice as likely to develop diabetes(糖尿病) as those who are the most active. She also found that the immobile are twice as likely to die from a heart attack and two-and-a-half times as likely to suffer cardiovascular disease as the most mobile. Crucially, all this seemed to be independent of the amount of vigorous, gym-style exercise that volunteers did.

    "If they hated me they didn't talk to me about it," says a young German manager at a media firm in Frankfurt. Still, he says it was noticeable that when an employee 20 years older than him thanked him for buying lunch he had to swallow twice before adding the word "boss".

    Older workers sometimes envy being managed by a younger colleague. Precocious (老成的) youngsters, too, can feel awkward about bossing their elders around. But in Germany a shortage of skilled workers means that such situations are becoming even more common.

    The country's population is projected to shrink. As more Germans retire, fewer youngsters are entering the work-place to replace them. As a share of the working population the number of 15-to-24-year-olds has fallen by ten percent since the 1980s, says the German Federal Employment Agency. Firms competing to hire young talent have to promote them earlier as a result. A paper by professors at the university of Cambridge and WHU, a German business school, to be published in the Journal of Organizational Behavior, suggests this could be a problem.

    As in many countries, German work-places are legally obliged to overlook age when deciding whom to promote. Yet according to Jochen Menges, one of the authors, when an ordinary worker leap-frogs a more experienced one it can leave the latter with feelings of "anger, fear and disgust." People tend to judge their own standing by the success of their peers, and to see failure in being bossed about by someone younger. The relationship between feelings of anxiety and the age of the boss is clear, according to Mr Menges. A manager who is younger by one year is somewhat unsettling; a gap of 20 years is far more discouraging.

    German firms certainly shouldn't return to a system in which age equals to rank. But young people tend to be sensitive about managing upwards. And older workers should be encouraged to see the bright side of learning new skills. Daimler, a big German car firm, says it promotes age- mixed teams, so that knowledge can be transferred between generations. It also supports young managers by asking retired employees to provide temporary support.

Biofuels (生物燃料), gained from plants and animal matter, are a key solution to the environmental problems caused by fuels like coal. "Bioalcohol (生物酒精) is the most common biofuel and is produced by sugars found in materials such as corn. With some engine redesigned, it can be used directly by cars, buses, etc. ," says Professor Daniel Tan, "12 percent of transport fuel could come from biofuels, especially bioalcohol, by 2030. "

But a 2016 study of biofuels said, "Bioalcohol presently is mostly produced with food crops. Altogether, the environmentally-friendly biofuels rely on about 2-3 percent of the global water and land used for agriculture, which could feed a large number of hungry people. "

Energy experts have therefore been trying to deal with the problem. Recent research led by an international team found that the agave (龙舌兰) plant might offer a way out. This plant tends to be the right bioalcohol source to supersede others such as sugarcane (甘蔗) and corn.

Daniel Tan explains that the agave can be grown in unfavorable conditions and is not a major food crop. "It can grow in areas that lack water and rainfall without being watered by farmers, and it does not compete with food crops or put demands on limited water. This kind of useful plant is recently being grown in Australia. It can survive Australia's hot summers," he says.

The study finds that sugarcane produces just a little more fuel per square meter each year than the agave. However, the agave outperforms sugarcane in a range of areas, including pollution to the earth, and water using. The agave uses 69 percent less water than sugarcane and 46 percent less water than corn for the same amount of fuel produced. As for corn，it produces less fuel per square meter each year than the agave.

However, Daniel Tan states: "The first generation of bioalcohol from the agave recently faces a big competition from oil, whose recent low price makes it far more attractive to customers. Without some policy support from the government, bioalcohol production from the agave faces big challenges. "