A long-term American study shows the importance of early education for poor children. The study is known as the Abecedarian Project. It involved more than one-hundred young children from poor families in North Carolina.

    Half of the children attended an all-day program at a high-quality child-care center. The center offered educational, health and social programs. Children took part in games and activities to increase their thinking and language skills and social and emotional development. The program also included health foods for the children.

    The children attended the program from when they were a few weeks old until the age of five years. The other group of children did not attend the child-care center. After the age of five, both groups attended public school.

    Researchers compared the two groups of children. When they were babies, both groups had similar results in tests for mental and physical skills. However, from the age of eighteen months, the children in the educational child-care program did much better in tests.

    The researchers tested the children again when they were twelve and fifteen years old. The tests found that the children who had been in the child-care center continued to have higher average test results. These children did much better on tests of reading and mathematics.

    A few years ago, organizers of the Abecedarian Project tested the students again. At the time, each student was twenty-one years old. They were tested for thinking and educational ability, employment, parenting and social skills. The researchers found that the young adults who had the early education still did better in reading and mathematics tests. They were more than two times as likely to be attending college or to have completed college. In addition, the children who received early education were older on average, when their first child was born.

    The study offers more evidence that learning during the first months and years of life is important for all later development.

    The researchers of the Abecedarian Project believe their study shows a need for lawmakers to spend money on public early education. They believe these kinds of programs could reduce the number of children who do not complete school and are unemployed.

    “Keep out or I'll chase you out! This is my property!” You hear this every spring. It is a long musical sound —a bird song! Birds use their songs to communicate different messages to one another. People who study bird sounds are learning their meanings.

    Usually it is the male that sings. Early in spring he sings to say that he has picked out a piece of property. He sings to attract a female of his same kind. Together they will raise a family in his territory (领地). He sings to tell all other birds of his kind to keep out.

    Each kind of bird has its own type of song. Cardinals sing something that sounds a little like “What cheer, cheer, cheer.” Towhees sing, “Drink your tea.”

    Most of the time, birds pay attention only to the songs of birds of their own kind. Cardinals answer cardinals, and song sparrows answer song sparrows. A cardinal knows that a song sparrow will not try to steal its mate. So you can see one reason why a cardinal may chase away another cardinal but will not bother a song sparrow.

    Most different kinds of birds eat different things. To find enough to eat, a bird needs a big piece of land to search in. Many kinds of birds have some ways of dividing up the land into territories. Song sparrows, cardinals ovenbirds, and white-throated sparrows are some of the birds that have territorial systems.

    Especially in early spring, birds work out the boundaries between their territories by singing “keep out” threats and by chasing and fighting each other. The birds continue singing to tell females that they have set up territories. Neighboring birds seem to agree that there are make believe fences between their pieces of property. Then they do not have to waste energy chasing each other instead of taking care of their young.

    Scientists guessed that some birds could recognize their neighbors by small differences in their songs. Two scientists who studied white-throated sparrows found that these birds can even tell the difference between songs of individual birds of their own kind. White-throated sparrows have songs that seem to say “I'm your neighbor” or “I'm a stranger” or “I'm your neighbor to the west.” Other kinds of birds could tell neighbors from strangers by their songs, too.

    On Sept. 15, TripAdvisor, one of the world's largest travel review websites, named the world's top 25 museums in its Travelers' Choice Award according to the reviews and opinions of travelers worldwide. Now let's take a look at the top four museums which are ranked as follows by the popularity around the world.

    Metropolitan Museum of Art, New York City

    It is the largest museum in the Western Hemisphere, with a collection of 2 million items from more than 5,000 years of world culture. The iconic museum includes important collections from ancient Egypt and medieval Europe as well as ancient Greece and Rome. Here, visitors can get lost in different centuries: They can see the Temple of Dendur from early Egypt, Dutch painter Vincent van Gogh's Wheatfield With Cypresses an US pop Andy Warhol's Souper Dress, all in one place.

    Muse d'Orsay, Paris

    Located in the center of Paris on the bank of the River Seine, the Musee d'Orsay houses the world's most amazing collections of impressionist and post-impressionist art. It offers the chance to view major works from greats like Van Gogh and Claude Monet. The museum is famous for being home to Starry Night over the Rhone, an oil painting by Van Gogh that is often praised along with his masterpiece Starry Night.

    Art Institute of Chicago, Illinois

    It was named the world's best museum in 2014. The world-famous Windy City museum houses nearly 300,000 works, including one of the largest collections of modern art, including pieces such as Spanish painter Pablo Picasso's The Old Guitarist, US artist Georgia O'Keeffe's Black Cross and French artist Henri Matisse's Bathers by a River. A TripAdvisor reviewer commented, “No matter how many times I visit, it never gets old. Paintings from every era, works from every great artist.”

    Museo Nacional del Prado, Madrid

    Nowhere is able to present the entire history of Spanish art like the Museo Nacional del Prado.

    Here, visitors can enjoy a detailed view of the Spanish school of the Modem Age. Outstanding masterpieces by artists such as Diego Velazquez, Francisco Goya and Joaquiin Sorolla make up an internationally-famous collection. The Italian school is another highlight of the museum's collection, as it includes the 15^th century masterpieces such as The Annunciation by Fra Angelico, The Death of the Virgin by Andrea Mantegna and The Dead Christ Supported by Angels by Antonello da Messina.

    Bees in a colony work with each other to gather food, and they try to find the most nectar (花蜜)in the least amount of time possible. A small number of bees work as searchers, but when a good flower patch (花丛) is found, how do they tell other bees where to find it?

    Bees communicate flower location using special dances inside the hive, where bees live. One bee dances while the other bees watch. The dancing bee smells like the flower patch, and also gives the watching bees a taste of the nectar she has gathered. Smell and taste helps other bees find the correct flower patch. Bees use two different kinds of dances to communicate information: the waggle (摇摆) dance and the circle dance.

    Waggle dance

    The waggle dance tells the watching bees two things about a flower patch's location: the distance and the direction away from the hive.

A. Distance

    The dancing bee waggles back and forth as she moves forward in a straight line, then circlesaround to repeat the dance. The length of the middle line, called the waggle run, shows roughly how far it is to the flower patch.

B. Direction

    Bees know which way is up and which way is down inside their hive, and they use this to show direction. How? Bees dance with the waggle run at a specific angle away from straight up. Outside the hive, bees look at the position of the sun, and fly at the same angle away from the sun.

    Circle dance

    The circle dance tells the watching bees only one thing about the flower patch's location: that it is somewhere close to the hive.

    In this dance, the bee walks in a circle, turns around, then walks the same circle in the opposite direction. Sometimes, the bee includes a little waggle as she's turning around. The duration of this waggle is thought to indicate the quality of the flower patch.

    Only about 30 percent of people in the US know how to perform CPR (心肺复苏术). Recently, a 9-year-old boy showed a Georgia woman how to perform CPR on her newborn baby.

    Susanna Rohm said she had experienced a parent's worst nightmare (噩梦) — her 2-month-old son, Isiah, was not breathing. "I noticed he looked pale. I looked at his arms and his legs and they were limp (无力的)," Rohm told a local newspaper. "Then I noticed that he looked like he wasn't alive." Indismay, she dropped and broke her cellphone. Rohm had to run into the street, screaming for help.

    "I had him in my arms and screamed over and over. Then I ran outside. I saw two boys playing across the street, and I yelled, 'Go and ask your parents to call 911,'" Rohm said. But the two boys were able to do more than that. Nine-year-old Ethan Wilson took action, showing Rohm how to perform CPR on little Isiah while ten-year-old Rocky Hurt helped as well.

    Rocky said he had learned the CPR technique from a poster in a health class at their school, Sedalia Park Elementary. "I was thinking we'd better give her a helping hand instead of getting scared," Ethan said. "I told her to push on the baby's chest five to ten times a minute with only two fingers, tilt back the baby's head, plug the baby's nose and breathe into the baby's mouth," Ethan said in an interview.

    At last, Isiah began crying and was breathing again. He spent two nights in a local hospital. "If the little boy hadn't shown me what to do right there, my baby would probably not be alive right now," Rohm said.

    On a recent spring morning. Susan Alexander, a retired government intelligence analyst, left her Maryland home, climbed into her Volkswagen Passat and drove about three miles to pick up two strangers. She battled rush-hour traffic on the Capital Beltway and George Washington Memorial Parkway before dropping them off at Reagan National Airport. She didn't earn a cent for her trouble, and that was the point.

    Alexander is a member of the Silver Spring Time Bank— one of more than 100 such exchanges around the world trying to build community by exchanging time credits for services instead of dollars and cents. "I have time," she said. "I like giving the gift of time to other people."

    In Alexander's case, passengers Mary and Al Liepold were grateful for the ride, but it wasn't charity. Mary, a retired writer and editor for nonprofit organizations, used time credits she banked for editing work and baking. Senior citizens who don't drive, the Liepolds cashed in their credits to catch a flight to Montreal for a five-day vacation.

    Without money changing hands or shifting between virtual accounts, the airport drop-off was more like a coffee party than a taxi ride. Driver and passengers chatted about projects they've completed for the time bank, and no one raised an eyebrow when Mary said she likes "to avoid the conventional economy."

    "The beauty of this is that you make friends," Mary Liepold said. "You don't just get services."

    The Silver Spring Time Bank formed in 2015 and has about 300 members, said co-founder Mary Murphy. Last year, she said, l,000 hours were exchanged for basic home repairs, dog walking, cooking and tailoring, among other services, without the exchange of money." You get to save that money that you would have spent," she said. "You get to meet somebody else in your community and get to know that person. That's a bonus that's part of an exchange."

    A deal performed partly to make friends would seem to go against classical economics and one of Benjamin Franklin's most memorable sayings: "Time is money." To those at the forefront of modern time-banking, that is the appeal.