The American literature is from the Romanticism to the Realism.

    The American Romanticism began from the end of 18th century to the outbreak of the Civil War, which is also called the American Renaissance. The period is as well as the time of American Westward Expansion. During the period, there were lots of workforces crowding to the cities, which promoted the industry.  The people found that they need their-own literature to record their experiences. So the Romanticism flourished(繁荣）.

    The Romanticism in American literature focuses on imagination and emotional factors. The American writers paid more attentions to the free expression of feelings and the characters' inner world. During the romantic period, there were many writers: Philip Freneau, William Cullen Bryant and so on.

    The Realism in American literature was from 1865 to 1914, and it takes on the American spirit, especially in American stories. The Realism against the Romanticism, advocates the people to come down to the earth and get rid of daydreams.

    During the 50 years from the Civil War to the WWI, the America had experienced a great change on many aspects, such as the politics, economy, culture and religion. It had changed the nature and the idea of the American society. The writers of new age didn't agree with the Romanticism of the old age.They were interested in real life and wanted to explain everything relating to the real life, which is to claim the objective reality, to get rid of idealism and Romanticism.

    There were 3 main writers at that time: William Peanoweils, Henry James and Mark Twain. Their writings represented the American native customs with their deep rural styles, which uncovered the people's inner life.

    Most people know precious gemstones (宝石) by their appearances. An emerald flashes deep green, a ruby seems to hold a red fire inside, and a diamond shines like a star. It's more difficult to tell where the gem was mined, since a diamond from Australia or Arkansas may appear the same to one from the Democratic Republic of the Congo. However, recently, a team of scientists has found a way to identify a gemstone's origin.

    Beneath the surface of a gemstone, on the tiny level of atoms and molecules（分子）, lie clues (线索) to its origin. At this year's meeting of the Geological Society of America in Minneapolis, Catherine McManus reported on a technique that uses lasers (激光) to clarify these clues and identify a stone's homeland. McManus directs scientific research at Materialytics, in Killeen, Texas. The company is developing the technique. “With enough data, we could identify which country, which mining place, even the individual mine a gemstone comes from,” McManus told Science News.

    Some gemstones, including many diamonds, come from war-torn countries. Sales of those “blood minerals” may encourage violent civil wars where innocent people are injured or killed. In an effort to reduce the trade in blood minerals, the U.S. government passed law in July 2010 that requires companies that sell gemstones to determine the origins of their stones.

    To figure out where gemstones come from, McManus and her team focus a powerful laser on a small sample of the gemstone. The technique is called laser-induced breakdown spectroscopy. Just as heat can turn ice into water or water into steam, energy from the laser changes the state of matter of the stone. The laser changes a miniscule part of the gemstone into plasma, a gas state of matter in which tiny particles（微粒）called electrons separate from atoms.

    The plasma, which is superhot, produces a light pattern. (The science of analyzing this kind of light pattern is called spectroscopy.) Different elements produce different patterns, but McManus and her team say that gemstones from the same area produce similar patterns. Materialytics has already collected patterns from thousands of gemstones, including more than 200 from diamonds. They can compare the light pattern from an unknown gemstone to patterns they do know and look for a match. The light pattern acts like a signature, telling the researchers the origin of the gemstone.

    In a small test, the laser technique correctly identified the origins of 95 out of every 100 diamonds. For gemstones like emeralds and rubies, the technique proved successful for 98 out of every 100 stones. The scientists need to collect and analyze more samples, including those from war-torn countries, before the tool is ready for commercial use.

    Scientists like Barbara Dutrow, a mineralogist from Louisiana State University in Baton Rouge, find the technique exciting. “This is a basic new tool that could provide a better fingerprint of a material from a particular locality,” she told Science News.

    Have you ever lost your direction? Then you might find satellite navigation(satnav) systems(卫星定位系统) helpful.

    A satnav system uses groups of satellites. They send information to a receiver(接收器), such as your smartphone. Then they can find where you are.

The earliest satnav system is the Global Positioning System(GPS) of the United States. The US has put 24 satellites into space to make sure GPS can locate(定位) a person correctly and globally. Likewise, Russia's GLONASS and European Union's Galileo can also work globally.

    But China is catching up, building its own BeiDou Navigation Satellite System. BeiDou is China's homegrown satnav system, reported Xinhua. It was set up in 2000, when China sent BeiDou's first navigation experiment satellite into space. With it, China became the third country to build a satnav system after the US and Russia.

    BeiDou can find you wherever you are. It helps you go faster by finding shortcuts(捷径) and using correct directions. When you are in trouble and call the police, they will know exactly where you are if you have a cellphone that uses BeiDou.

    Today, there are more than 20 BeiDou satellites above our heads. And the system is able to offer open services to the Asia-Pacific region(亚太地区).

    In November, China plans to send more BeiDou-3 satellites into space. BeiDou-3's position accuracy(准确度) is less than five meters, Ran Chengqi, a senior designer of the satellite navigation system, told China Daily.

    By 2020, BeiDou is planned to have 35 satellites and begin serving globally, reported Xinhua.

    Every man wants his son to be somewhat of a clone（克隆）, not in features but in footsteps. As he grows you also age, and your ambitions become more unachievable. You begin to realize that your boy, in your footsteps, could probably achieve what you hoped for. But footsteps can be muddied and they can go off in different directions.

    My son Jody has hated school since day one in kindergarten. Science projects waited until the last moment. Book reports weren't written until the final threat.

    I've been a newspaperman all my adult life. My daughter is a university graduate working toward her master's degree in English. But Jody? When he entered the tenth grade he became a "vo-tech" student (技校学生). They're called "motorheads" by the rest of the student body.

    When a secretary in my office first called him "motorhead", I was shocked. "Hey, he's a good kid," I wanted to say. "And smart, really."

    I learned later that motorheads are, indeed, different. They usually have dirty hands and wear dirty work clothes. And they don't often make school honor rolls (光荣榜).

    But being the parent of a motorhead is itself an experience in education. We who labor in clean shirts in offices don't have the abilities that motorheads have. I began to learn this when I had my car crashed. The cost to repair it was estimated at $800. "Hey, I can fix it," said Jody. I doubted it, but let him go ahead, for I had nothing to lose.

    My son, with other motorheads, fixed the car. They got parts (零件）from a junkyard, and ability from vo-tech classes. The cost was $25 instead of $800.

    Since that first repair job, a broken air-conditioner, a non-functioning washer and a non-toasting toaster have been fixed. Neighbors and co-workers trust their car repairs to him.

    These kids are happiest when doing repairs. They joke and laugh and are living in their own relaxed world. And their minds are bright despite their dirty hands and clothes.

    I have learned a lot from my motorhead: publishers need printers, engineers need mechanics, and architects need builders. Most important, I have learned that fathers don't need clones in footsteps or anywhere else.

    My son may never make the school honor roll. But he made mine.

    Last summer, bird-watchers confirmed the discovery of a new species of bird in Cambodia was not an event of particular biological significance, but it was striking for one reason in part. This species of bird was discovered not in an unspoiled rain forest but within the limits Cambodia's capital, Phnom Penh – a city the size of Philadelphia.

What the researchers found was surprising in cities. The medium-sized city in the state about 110 species of birds, over 95 percent of which would have been growing there urbanization. Ecologically speaking, cities are different, concrete buildings. Rather, each unique bio-profile – a kind of ecological fingerprint – that is against the idea of an environment dead zone.

    Of course, it's also true that in the world of birds and plants, as in human society, there is such a thing as worldwide—the city-inhabitants who feel equally at home in San Francisco, Milan and Beijing. Four birds occur in more than 80 percent of the cities studied, and 11 plants occurred in more than 90 percent of the cities. On the plant side, those are seemingly spread by European settlement. In the air, it's the usual suspects: the rock pigeon and many other birds. “They have become completely adapted to urban life,”Katti says. “That's not much of surprise. But they don't actually dominate as much as we think they do.” Those species—occurring in the cities across the globe—represent only a small part of a city's natural varieties.

    Not all cities are equal protectors of native animals and plants, though. One of the biggest predictors for a city's biodiversity is its urban design. Territory as varied as backyards and street trees can lay important roles in greening a city. In fact, the amount of green space is a stronger predictor of the density of biodiversity than a city's size. A metropolis with a sizable network of parks can contain more species per square mile than a much smaller city.

    In a world where architecture, food, language, fashion and commerce are increasingly globalized, a city's native animals and plants can be a kind of identity. There may be neighborhoods in London and Paris that resemble Singapore or Hong Kong. Cities are becoming similar, but their natural environments stand completely apart.

    Everyday Food by Martha Stewart

    No matter how busy you are, at the end of the day you want meals that are easy to prepare. And you want lots of choices and variations. You'll find all of that in this book: 250 simple recipes for delicious meals that bring freshness and nutrition.

    Paperback, published by Random House, $16.79

    Zeroes

    By Scott Westerfeld, Margo Lanagan, Deborah Biancotti

    The New York Times best-selling author Scott Westerfeld teams up with Margo Lanagan and Deborah Biancotti in the book about six teenagers with amazing abilities. These teenagers have powers that set them apart. They can do things ordinary people can't.

    Paperback, published by Simon & Schuster, $12.99

    Mighty Jack

    By Ben Hatke

    Jack dislikes summer. But he's got a good reason: summer is when his single mom takes a second job and leaves him at home to watch his sister, Maddy. It's lots of responsibility, and it's boring, too, because Maddy doesn't talk. But one day, at the market, Maddy does talk—to tell Jack to trade their mom's car for a box of mysterious seeds. It's the best mistake Jack has ever made.

    Hardcover, published by First Second, $14.15

    Only Daughter

    By Anna Snoekstra

    She's caught stealing. She's homeless and on the run. But she happens to look the same as a girl who went missing a decade ago, Rebecca Winter. She takes Rebecca's identity, using it as a way out. Little does she know her new life as Rebecca is itself a prison and it looks like a killer might be after her.

    Kindle edition, published by Harlequin Enterprises, $8.88