Languages have been coming and going for thousands of years, but in recent times there has been less coming and a lot more going. When the world was still populated by hunter-gatherers, small, tightly knit (联系)groups developed their own patterns of speech independent of each other.Some language experts believe that 10,000 years ago, when the world had just five to ten million people, they spoke perhaps 12,000 languages between them.

Soon afterwards, many of those people started settling down to become farmers, and their languages too became more settled and fewer in number. In recent centuries, trade, industrialization, the development of the nation-state and the spread of universal compulsory education, especially globalisation and better communications in the past few decades, all have caused many languages to disappear, and dominant languages such as English, Spanish and Chinese are increasingly taking over.zxxk

At present, the world has about 6,800 languages. The distribution of these languages is hugely uneven. The general rule is that mild zones have relatively few languages, often spoken by many people, while hot, wet zones have lots, often spoken by small numbers. Europe has only around 200 languages; the Americas about 1,000; Africa 2 400; and Asia and the Pacific perhaps 3,200, of which Papua New Guinea alone accounts for well over 800. The median number (中位数)of speakers is a mere 6,000, which means that half the world’s languages are spoken by fewer people than that.

Already well over 400 of the total of, 6,800 languages are close to extinction(消亡), with only a few elderly speakers left. Pick, at random, Busuu in Cameroon (eight remaining speakers),Chiapaneco in Mexico(150), Lipan Apache in the United States(two or three)or Wadjigu in Australia (one, with a question-mark): none of these seems to have much chance of survival.

  As cultural symbols go， the American car is quite young． The Model T Ford was built at the Piquette Plant in Michigan a century ago， with the first rolling off the assembly line （装配线）on September 27， 1908． Only eleven cars were produced the next month． But eventually Henry Ford would build fifteen million of them．

    Modern America was born on the road，behind a wheel． The car shaped some of the most lasting aspects of American culture： the roadside diner， the billboard， the motel，even the hamburger． For most of the last century， the car represented what it meant to be American﹣going forward at high speed to find new worlds． The road novel， the road movie， these are the most typical American ideas， born of abundant petrol， cheap cars and a never﹣ending interstate highway system， the largest public works project in history．

    In 1928 Herbert Hoover imagined an America with "a chicken in every pot and a car in every garage．" Since then， this society has moved onward， never looking back， as the car transformed America from a farm﹣based society into an industrial power．

    The cars that drove the American Dream have helped to create a global ecological disaster． In America the demand for oil has grown by 22 percent since 1990．

    The problems of excessive（过度的） energy consumption， climate change and population growth have been described in a book by the American writer Thomas L． Friedman． He fears the worst， but hopes for the best．

    Friedman points out that the green economy（经济）is a chance to keep American strength． "The ability to design， build and export green technologies for producing clean water， clean air and healthy and abundant food is going to be the curreney of power in the new century．"

Many of us love July because it’s the month when nature’s berries and stone fruits are in abundance. These colourful and sweet jewels from British Columbia’s fields are little powerhouses of nutritional protection.

Of the common berries, strawberries are highest in vitamin C, although, because of their seeds, raspberries contain a little more protein (蛋白质), iron and zinc (not that fruits have much protein). Blueberries are particularly high in antioxidants (抗氧化物质). The yellow and orange stone fruits such as peaches are high in the carotenoids we turn into vitamin A and which are antioxidants. As for cherries (樱桃), they are so delicious who cares? However, they are rich in vitamin C.

When combined with berries or slices of other fruits, frozen bananas make an excellent base for thick, cooling fruit shakes and low fat “ice cream”. For this purpose, select ripe bananas for freezing as they are much sweeter. Remove the skin and place them in plastic bags or containers and freeze. If you like, a squeeze of fresh lemon juice on the bananas will prevent them turning brown. Frozen bananas will last several weeks, depending on their ripeness and the temperature of the freezer.

If you have a juicer, you can simply feed in frozen bananas and some berries or sliced fruit. Out comes a “soft-serve” creamy dessert, to be eaten right away. This makes a fun activity for a children’s party; they love feeding the fruit and frozen bananas into the top of the machine and watching the ice cream come out below.

Fire Prevention Information

    The University of Adelaide employs a full﹣time staff of fire prevention professionals． They inspect all campus buildings and test and maintain all sprinkler（喷水灭火装置） systems，fire alarms，and fire extinguishers（灭火器）． They also provide educational programs on fire safety in the residence halls． Whenever you move to a new area， you should locate the fire alarm pull stations and the two exits nearest your room．

Fire Alarms

    The floors of all campus buildings are equipped with manual（手动的）fire alarm systems which include fire alarm pull stations and pipes． Most are also equipped with automatic fire alarm systems consisting of heat detectors， smoke detectors and sprinklers． For your safety，never tamper with（胡乱摆弄） these systems． False fire alarms are illegal and may lead to imprisonment．

Fire Drills

    A fire drill will be conducted in your residence hall every semester． During a fire drill，please do the following：

    •Take your room key and ID，close and lock the door to your room．

    •Exit immediately from the nearest emergency exit；do not use a lift．

    •Meet outside of your residence hall and wait for further instructions．

Fire Extinguishers

    Fire extinguishers are located on each floor and in each apartment． Use a fire extinguisher only if you have been trained to do so． Irresponsible use of a fire extinguisher can create a dangerous situation for other residents and could result in damage to personal property． Misuse of a fire extinguisher will result in fines．

Smoke Detectors

    A smoke detector is on the ceiling in your room． Some buildings also have heat detectors on the ceilings． Do the following to ensure the safe operation of your smoke detector：

    •If your smoke detector is working properly， the red light should be on． If the red light is not blinking（闪动）， contact residence hall staff immediately．

    •Do not cover or block your smoke detector in any way．

    •If a smoke detector sets off an alarm and there is no fire or smoke， inform your hall staff．

Give yourself a test. Which way is the wind blowing? How many kinds of wildflowers can be seen from your front door? If your awareness is as sharp as it could be, you’ll have no trouble answering these questions.

Most of us observed much more as children than we do as adults. A child’s day is filled with fascination, newness and wonder. Curiosity gave us all a natural awareness. But distinctions that were sharp to us as children become unclear; we are numb(麻木的）to new stimulation(刺激), new ideas. Relearning the art of seeing the world around us is quite simple, although it takes practice and requires breaking some bad habits.

The first step in awakening senses is to stop predicting what we are going to see and feel before it occurs. This blocks awareness. One chilly night when I was hiking in the Rocky Mountains with some students, I mentioned that we were going to cross a mountain stream. The students began complaining about how cold it would be. We reached the stream, and they unwillingly walked ahead. They were almost knee-deep when they realized it was a hot spring. Later they all admitted they’d felt cold water at first.

Another block to awareness is the obsession(痴迷) many of us have with naming things. I saw bird watchers who spotted a bird, immediately looked it up in field guides, and said, a "ruby-crowned kinglet" and checked it off. They no longer paid attention to the bird and never learned what it was doing.

The pressures of "time" and "destination" are further blocks to awareness. I encountered many hikers who were headed to a distant camp-ground with just enough time to get there before dark. It seldom occurred to them to wander a bit, to take a moment to see what’s around them. I asked them what they’d seen. "Oh, a few birds," they said. They seemed bent on their destinations.

Nature seems to unfold to people who watch and wait. Next time you take a walk, no matter where it is, take in all the sights, sounds and sensations. Wander in this frame of mind and you will open a new dimension to your life.z.xxk

If you want to disturb the car industry， you'd better have a few billion dollars： Mom﹣and﹣pop carmakers are unlikely to beat the biggest car companies． But in agriculture， small farmers can get the best of the major players． By connecting directly with customers， and by responding quickly to changes in the markets as well as in the ecosystems（生态系统）， small farmers can keep one step ahead of the big guys． As the co﹣founder of the National Young Farmers Coalition （NYFC， 美国青年农会）and a family farmer myself， I have a front﹣row seat to the innovations among small farmers that are transforming the industry．

    For example， take the Quick Cut Greens Harvester， a tool developed just a couple of years ago by a young farmer， Jonathan Dysinger， in Tennessee， with a small loan from a local Slow Money group． It enables small﹣scale farmers to harvest 175 pounds of green vegetables per hour﹣a huge improvement over harvesting just a few dozen pounds by hand﹣suddenly making it possible for the little guys to compete with large farms of California． Before the tool came out， small farmers couldn't touch the price per pound offered by California farms． But now， with the combination of a better price point and a generally fresher product， they can stay in business．

    The sustainable success of small farmers， though， won't happen without fundamental changes to the industry． One crucial factor is secure access to land． Competition from investors，developers， and established large farmers makes owning one's own land unattainable for many new farmers．From 2004 to 2013， agricultural land values doubled， and they continue to rise in many regions．

    Another challenge for more than a million of the most qualified farm workers and managers is a non﹣existent path to citizenship ﹣ the greatest barrier to building a farm of their own． With farmers over the age of 65 outnumbering（多于）farmers younger than 35 by six to one， and with two﹣thirds of the nation's farmland in need of a new farmer， we must clear the path for talented people willing to grow the nation's food．

    There are solutions that could light a path toward a more sustainable and fair farm economy，but farmers can't clumsily put them together before us． We at the NYFC need broad support as we urge Congress to increase farmland conservation， as we push for immigration reform， and as we seek policies that will ensure the success of a diverse and ambitious next generation of farmers from all backgrounds． With a new farm bill to be debated in Congress， consumers must take a stand with young farmers．

We may think we're a culture that gets rid of our worn technology at the first sight of something shiny and new, but a new study shows that we keep using our old devices(装置) well after they go out of style. That’s bad news for the environment — and our wallets — as these outdated devices consume much more energy than the newer ones that do the same things.

To figure out how much power these devices are using, Callie Babbitt and her colleagues at the Rochester Institute of Technology in New York tracked the environmental costs for each product throughout its life — from when its minerals are mined to when we stop using the device. This method provided a readout for how home energy use has evolved since the early 1990s. Devices were grouped by generation. Desktop computers, basic mobile phones, and box-set TVs defined 1992. Digital cameras arrived on the scene in 1997. And MP3 players, smart phones, and LCD TVs entered homes in 2002, before tablets and e-readers showed up in 2007.

As we accumulated more devices, however, we didn't throw out our old ones. "The living-room television is replaced and gets planted in the kids' room, and suddenly one day, you have a TV in every room of the house," said one researcher. The average number of electronic devices rose from four per household in 1992 to 13 in 2007. We're not just keeping these old devices — we continue to use them. According to the analysis of Babbitt's team, old desktop monitors and box TVs with cathode ray tubes are the worst devices with their energy consumption and contribution to greenhouse gas emissions（排放）more than doubling during the 1992 to 2007 window.

So what's the solution（解决方案）? The team's data only went up to 2007, but the researchers also explored what would happen if consumers replaced old products with new electronics that serve more than one function, such as a tablet for word processing and TV viewing. They found that more on-demand entertainment viewing on tablets instead of TVs and desktop computers could cut energy consumption by 44%.

Teens and younger children are reading a lot less for fun, according to a Common Sense Media report published Monday.

While the decline over the past decade is steep for teen readers, some data in the report shows that reading remains a big part of many children’s lives, and indicates how parents might help encourage more reading.

According to the report’s key findings, “the proportion (比例) who say they ‘hardly ever’ read for fun has gone from 8 percent of 13-year-olds and 9 percent of 17-year-olds in 1984 to 22 percent and 27 percent respectively today.”

The report data shows that pleasure reading levels for younger children, ages 2-8, remain largely the same. But the amount of time spent in reading each session has declined, from closer to an hour or more to closer to a half hour per session.

When it comes to technology and reading, the report does little to counsel (建议) parents looking for data about the effect of e-readers and tablets on reading. It does point out that many parents still limit electronic reading, mainly due to concerns about increased screen time.

The most hopeful data shared in the report shows clear evidence of parents serving as examples and important guides for their kids when it comes to reading. Data shows that kids and teens who do read frequently, compared to infrequent readers, have more books in the home, more books purchased for them, parents who read more often, and parents who set aside time for them to read.

As the end of school approaches, and school vacation reading lists loom (逼近) ahead, parents might take this chance to step in and make their own summer reading list and plan a family trip to the library or bookstore.

There’s a new frontier in 3D printing that’s beginning to come into focus: food. Recent development has made possible machines that print, cook, and serve foods on a mass scale. And the industry isn’t stopping there.

Food production

With a 3D printer, a cook can print complicated chocolate sculptures and beautiful pieces for decoration on a wedding cake. Not everybody can do that — it takes years of experience, but a printer makes it easy. A restaurant in Spain uses a Foodini to “re-create forms and pieces” of food that are “exactly the same,” freeing cooks to complete other tasks. In another restaurant, all of the dishes and desserts it serves are 3D-printed,rather than farm to table.

Sustainability(可持续性）

The global population is expected to grow to 9.6 billion by 2050, and some analysts estimate that food production will need to be raised by 50 percent to maintain current levels. Sustainability is becoming a necessity. 3D food printing could probably contribute to the solution. Some experts believe printers could use hydrocolloids(水解胶体) from plentiful renewables like algae(藻类) and grass to replace the familiar ingredients(烹饪原料). 3D printing can reduce fuel use and emissions. Grocery stores of the future might stock "food" that lasts years on end, freeing up shelf space and reducing transportation and storage requirements.

Nutrition

Future 3D food printers could make processed food healthier. Hod Lipson, a professor at Columbia University, said, “Food printing could allow consumers to print food with customized nutritional content, like vitamins. So instead of eating a piece of yesterday’s bread from the supermarket, you’d eat something baked just for you on demand.”

Challenges

Despite recent advancements in 3D food printing, the industry has many challenges to overcome. Currently, most ingredients must be changed to a paste(糊状物) before a printer can use them, and the printing process is quite time-consuming, because ingredients interact with each other in very complex ways. On top of that, most of the 3D food printers now are restricted to dry ingredients, because meat and milk products may easily go bad. Some experts are skeptical about 3D food printers, believing they are better suited for fast food restaurants than homes and high-end restaurants.