The term “formal learning” refers to all learning which takes place in the classroom regardless of whether such learning is informed by conservative or progressive ideologies(思想意识). “Informal learning”, on the other hand, is used to refer to learning which takes place outside the classroom.

    These definitions(定义) provide the basic difference between the two models of learning. Formal learning is separated from daily life and may actually promote ways of learning and thinking which often run counter to those obtained form practical daily life. A characteristic feature of formal learning is the centrality of activities which can prepare for the changes of adult life outside the classroom, but it cannot, by its nature, consist of these challenges.

    In doing this, language plays an important role as a major channel for information exchange.  The language of the classroom is more similar to the language used by middle-class families than that used by working-class families. Middle class children thus find it easier to gain the language of the classroom than their working-class classmates.

Informal learning, in contrast, occurs in the setting to which it relates, making learning immediately relevant (相关的). In this context, language does not occupy such an important role: the child's experience of learning is more direct, involving sight, touch, taste, and smell senses that are not used in the classroom. Whereas formal learning is transmitted by teachers selected to perform this role, informal learning is gained as a natural part of child's socialization. Adults or older children who are proficient (熟练的) in skill or activity provide—sometimes unintentionally (无意义地)—target models of behavior in the course of everyday activity.

    Informal learning, therefore, can take place at any time and place. The motivation of learner provides another important difference between the two models of learning. The formal learner is generally motivated by some kind of external goal such as parental approval, social status, and possible financial reward. The informal learner, however, tends to be motivated by successful completion of the task itself and the partial knowledge of adult status.

    Given that learning systems develop as a response to the social and economic contexts in which they are firmly, it is understandable that modern, high urbanized (城市化) societies have concentrated almost specially on the establishment of formal education systems. What these societies have failed to recognize are the ways in which formal learning inhibits the child's multi-sensory acquisition of practical skills. The failure to provide a child with a direct education may in part account for many of the social problems which trouble our societies.

    Most people want to know how things are made. They honestly admit, however, that they hardly know a thing when it comes to understanding how a piece of music is made. Where a composer (作曲家） begins, how he manages to keep going- in fact, how and when he learns his trade - all are covered in complete darkness. The composer, in short, is a man of mystery (神秘）.

    One of the first things the common man wants to know about is the part inspiration (灵感） plays in a composer's work. He finds it difficult to believe that composers are not much interested in that question. Writing music is as natural for the composer as eating or sleeping for all. Music is something that the composer happens to have been born for.

    The composer, therefore, does not say to himself: "Do I feel inspired?" He says to himself. "Do I feel like working today?" And if he feels like working, he does. It is more or less like saying to himself: "Do I feel sleepy?" if you feel sleepy, you go to sleep. If you don't feel sleepy you stay up. If the composer doesn't feel like working, he doesn't work. It's as simple as that.

    Throughout the world, parents talk differently to babies than they do to adults. With their young kids, parents use baby talks, featuring long pauses and a roller coaster of pitch（音高）changes.

    While parents may feel a bit silly using baby talks, they shouldn't in fact. Babies not only prefer listening to them, but they also learn new words more easily from them. By highlighting the structure of speech, such as the differences between the vowels（元音）“a” and “o”, baby talks help babies translate sounds into meaningful units of language.

    Actually, the timbre（音色）plays a role. The timbre of an instrument clearly affects how we experience music, but its role in language is less obvious. Looking into the timbre of baby talks, researchers made some surprising discoveries. In a new study published in Current Biology, researchers reported for the first time that mothers shifted their overall vocal timbre when speaking to their babies, as if they were changing their voice into a different instrument to address these unique little listeners.

    In the Princeton Baby Lab, where researchers study how children learn, they recorded English-speaking mothers while they talked with their 7-to-12-month-old babies and while they spoke to an adult experimenter, and found that adult-directed and baby-directed speech had consistently different timbres.

    Most surprising, in a second sample of non-English-speaking mothers, researchers found that this timbre shift was also highly consistent across nine diverse languages. This suggests these timbre shifts may represent a universal form of communication with babies.

    Being able to identify baby talks across multiple languages could give us rich information about the amount and type of language children hear at preschool across different cultural environments. This could help researchers and educators predict and improve outcomes such as vocabulary and success at school.

    Parents should feel self-conscious about their own baby talks: with them they're helping their baby learn.

    I grew up in Bensonhurst, Brooklyn. When the holiday decorations went up, there were houses on my block with trees lit up for Christmas in front yards and behind living room windows. I was born in a Jewish family. Even though I received eight presents for Hanukkah (an eight-day Jewish holiday in November or December), it just wasn't fair. My friends had beautiful trees with lights and presents brought by a man in a red suit. I didn't have a tree, and I lived in an apartment building, so I had no chimney(烟囱).

    That year, some neighbors bought a Christmas tree, but it was too tall for their living rooms. They cut off the top and, knowing I wanted to celebrate Christmas, gave the top to my family. After my parents fell asleep, I opened a window in our apartment. I imagined Santa could park his sleigh(雪橇) on our fire escape. When I woke up the next morning, the window was closed and Santa had delivered a present. I can't even remember what it was, but my memory of the morning lasts.

    My relationship with Santa took a break until my daughter, Amanda, was born in 1992. My wife and I saw no reason to deprive(剥夺) her of meeting Santa. In 1998, a friend of mine portrayed(扮演) Santa at the South Street Seaport in Manhattan. He told me to stop by with my wife and daughter, and asked for their names in advance so he could greet them. When he saw us at the seaport, he greeted us by our names. My daughter's mouth opened wide and she pulled back. Maybe she was too young to appreciate this. But other families waiting to see him seemed delighted by his appearance and the gifts he brought.

    My two children are now grown up and do not visit Santa, and we do not have a Christmas tree, yet our family still enjoys the holiday. On Christmas Eve, in the spirit of the night, we leave a plate of my favorite cookies on the kitchen table in hopes Santa will leave a present.

    The day will come when renewable energy such as wind, solar, geothermal and others replace fossil fuels as the major source of world energy. However, most analysts insist that this day will not arrive for many decades to come—certainly well past the middle of the century. Systems of fossil fuels have already been firmly set up, and it is too costly or impractical to replace the existing systems with renewables. But there are good reasons to believe that the transition (转变) to renewables will come much faster than previously thought.

    It is hardly surprising that many experts say we will see a relatively slow transition from fossil fuels to renewables, given what is known about previous energy changes of this sort. "Energy transitions take a long time," observed Vaclav Smil of the University of Manitoba in Scientific American. It took more than 50 years for coal to replace wood as the world's leading source of energy and another 50 years for oil to replace coal; the change from fossil fuels to renewables, he argued, is not likely to come any faster.

    Under ordinary circumstances, Smil's forecast would no doubt prove accurate. But these are not ordinary times. Growing concern over climate change is leading to increasingly strict controls on CO₂ and other greenhouse gas (GHG) emissions (排放), while the development in renewables technology is lowering their price and speeding their installation.

    There are, of course, many difficulties in the effective control of carbon emissions, as demonstrated by coal companies to block the introduction of new rules by the US Environmental Protection Agency. Nevertheless, it is impossible to dismiss the progress being made at the local and international levels to promote the use of renewables. The European Union (E. U), for example, is well on the way to achieving a 20% reduction in GHG emissions from 1990 levels by 2020, along with a 20% increase in the use of renewable energy.

    The transition to renewables will be faster due to dramatic improvements in the pricing and performance of such systems. As a result of the steady increases in the efficiency of wind and solar systems, together with the savings achieved through large-scale manufacture, the price of renewables is falling globally. With prices dropping this fast, solar energy is now proving competitive with fossil fuels for generating electricity in many areas.

    The change from fossil fuels to renewable energy will not come overnight, and it will not escape many setbacks. Nevertheless, renewables are likely to replace fossil fuels as the main source of electrical power well before mid-century.

    How did the sea horse get its name? It's not hard to guess. The top half of this fish looks like a small horse. But looking at the sea horse's tail, you might think "sea monkey" is a better name. Then there's the sea horse's pouch(袋). "Sea kangaroo" might also be a good name for this fish.

    Sea horses live in warm ocean waters all over the world. They keep safe from other fish by hiding in plants and grasses that grow under the sea. They can also change colors to match their surroundings(环境). A sea horse remains in one place for hours at a time by winding(缠绕)its tail around a plant. It feeds on live food, such as small shrimp. For a fish that doesn't move around much, the sea horse eats a lot--in just one day, a sea horse can eat 3,000 shrimp!

    A sea horse keeps the same mate for its whole life, and it's the male(雄的)sea horse that gives birth to baby sea horses. How does this happen? Baby sea horses start out as eggs, which come from the female's body. The male carries the eggs in its pouch for about three weeks until they hatch(孵化). Soon after the babies are born, the female gives her mate a new set of eggs. The male sea horse spends most of its life carrying eggs.

    Sadly, the number of sea horses is becoming smaller. Why is this happening? Some places where sea horses once lived have been filled in to make new land. Also, many sea horses are caught and sold as aquarium（水族馆，养鱼缸）fish. This really is not a good idea because most sea horses don't live long in aquariums. The best place for a sea horse is the ocean.