Humans have been keeping animals as pets for tens of thousands of years, but Dr Jean-Loup Rault, an animal scientist at the University of Melbourne in Australia, believes new companions are coming: robot pets.

    “Technology is moving very fast,” Rault told ABC News, “The Tamagotchi in the early 1990s was really the first robotic pet, and now Sony and other big companies have improved them a lot.”

    This may not sit well with pet lovers. After all, who would choose a plastic toy over a lovely puppy? But Rault argues that the robotic kind has a lot going for it: “You don't have to feed it, you don't have to walk it, it won't make a mess in your house, and you can go on a holiday without feeling guilty.” The technology also benefits those who are allergic to pets, short on space, or fearful of real animals.

    It's not clear whether robot pets can replace real ones. But studies do suggest that we can bond with these smart machines. People give their cars names and kids give their toy animals life stories. It's the same with robots. When Sony stopped its repair service for its robot dog Aibo in March 2014, owners in Japan held funerals.

    As an animal welfare researcher, Rault is concerned about how robotic pets could affect our attitudes towards live animals. “If we become used to a robotic companion that doesn't need food, water or exercises, perhaps it will change how humans care about other living beings,” he said.

    So are dogs and cats a thing of the past, as Rault predicts? For those who grew up with living and breathing pets, the mechanical kind might not do. But for our next generation who are in constant touch with smart technology, a future in which lovely pets needn't have a heartbeat might not be a far-fetched dream.

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

    Mark Twain has been called the inventor of the American novel. And he surely deserves additional praise: the man who popularized the clever literary attack on racism.

    I say clever because anti-slavery fiction had been the important part of the literature in the years before the Civil War. H. B. Stowe's Uncle Tom's Cabin is only the most famous example. These early stories dealt directly with slavery. With minor exceptions, Twain planted his attacks on slavery and prejudice into tales that were on the surface about something else entirely. He drew his readers into the argument by drawing them into the story.

    Again and again, in the postwar years, Twain seemed forced to deal with the challenge of race. Consider the most controversial, at least today, of Twain's novels, Adventures of Huckleberry Finn. Only a few books have been kicked off the shelves as often as Huckleberry Finn, Twain's most widely read tale. Once upon a time, people hated the book because it struck them as rude. Twain himself wrote that those who banned the book considered the novel “trash and suitable only for the slums (贫民窟).” More recently the book has been attacked because of the character Jim, the escaped slave, and many occurences of the word nigger. (The term Nigger Jim, for which the novel is often severely criticized, never appears in it.)

    But the attacks were and are silly—and miss the point. The novel is strongly anti-slavery. Jim's search through the slave states for the family from whom he has been forcibly parted is heroic. As J. Chadwick has pointed out, the character of Jim was a first in American fiction—a recognition that the slave had two personalities, “the voice of survival within a white slave culture and the voice of the individual: Jim, the father and the man.”

    There is much more. Twain's mystery novel Pudd'nhead Wilson stood as a challenge to the racial beliefs of even many of the liberals of his day. Written at a time when the accepted wisdom held Negroes to be inferior (低等的) to whites, especially in intelligence, Twain's tale centered in part around two babies switched at birth. A slave gave birth to her master's baby and, for fear that the child should be sold South, switched him for the master's baby by his wife. The slave's lightskinned child was taken to be white and grew up with both the attitudes and the education of the slave-holding class. The master's wife's baby was taken for black and grew up with the attitudes and intonations of the slave.

    The point was difficult to miss: nurture (养育), not nature, was the key to social status. The features of the black man that provided the stuff of prejudice—manner of speech, for example— were, to Twain, indicative of nothing other than the conditioning that slavery forced on its victims.

    Twain's racial tone was not perfect. One is left uneasy, for example, by the lengthy passage in his autobiography (自传) about how much he loved what were called “nigger shows” in his youth—mostly with white men performing in black-face—and his delight in getting his mother to laugh at them. Yet there is no reason to think Twain saw the shows as representing reality. His frequent attacks on slavery and prejudice suggest his keen awareness thattheydid not.

    Was Twain a racist? Asking the question in the 21st century is as wise as asking the same of Lincoln. If we read the words and attitudes of the past through the “wisdom” of the considered moral judgments of the present, we will find nothing but error. Lincoln, who believed the black man the inferior of the white, fought and won a war to free him. And Twain, raised in a slave state, briefly a soldier, and inventor of Jim, may have done more to anger the nation over racial injustice and awaken its collective conscience than any other novelist in the past century.

    It's a white Christmas in the United States today, with snow falling from Seattle to Maine.

    Northeast

    Biting winds with snow swept the Northeast.

    Earlier, up to 15 inches of snow fell during a snow storm in Maine, while up to one foot fell in New Hampshire. Winds reached 76 mph on Cape Cod, Massachusetts, while up to 61 mph winds tore through Long Island, New York. Falling snow collected on the runways at Boston's Logan International Airport, causing temporary flight delays.

    The wind was so severe in Pennsylvania and New Jersey that the annual (重演) of George Washington and his soldiers'crossing the Delaware River was canceled, the Washington Crossing Historic Park told ABC News.

    Midwest

    Heavy lake effect snow fell in western Michigan.

    The National Weather Service has issued a wind-chill warning and advisory (公告) from Montana to Michigan. Bitter cold air in the Midwest produced wind chills Monday morning as low as minus 48 degrees in North Dakota and minus 47 in northern Minnesota.

    As this bitter cold made its way east overnight, it was expected to move over relatively mild Great Lakes, producing intense lake-effect snow bands capabie of producing 2 to 4 inches of snow in an hour.

    West Coast

    That storm system moved overnight through the Rockies, bringing more snow and the threat of avalanches(雪崩). The National Weather Service has issued an avalanche warning for the Wasatch Range Mountains outside Salt Lake City.

Help Hermit Crabs

    Hermit crabs are nature's recyclers. They eat waste and help keep oceans and shores clean. Unlike other crabs, the hermit crab has a thin outer shell over its soft tail. This makes the hermit crab easy prey for hungry predators(天敌).Hermit crabs stay safe by living in old seashells. A hermit crab is picky(狡猾); it tries on many shells until it finds one that fits just right. In recent years, however, many hermit crabs have had trouble finding their perfect homes. What is the problems. There are not enough shells to go around!

    One reason for the seashell shortage is that ocean water is not as clean as it once was. This has caused chemical changes to sea water. Some sea animals, like snails, are affected by these changes.  Now there are fewer snails making shells. People visiting the beach often take shells home as souvenirs(纪念品).This is another problem. Other people even take shells for their own pet hermit crabs! They do not realize that hermit crabs in the wild need those shells too.

    Now people are working to solve this hermit crab housing shortage. They are teaching beach-Boers to leave seashells where they belong--at the seashore! Some people even make fake seashells that they hope the hermit crabs will like. For example, a group called Project Shelter invited people who visited their website to create different designs for hermit crab shells.

    These designers had a lot to consider. What kind of material should be used to build a seashells. The material must be light enough for the hermit crab to carry, but strong enough to protect the crab from predators. The man-made shells could not contain glue or any other substance(物质)that might harm a hermit crab. Another challenge with building a hermit crab home was the opening to the shell. Too big would mean the crab would not feel safe. Too small would be uncomfortable, and the crab would not want to move in.

    The Project Shelter shells are placed in the wild for hermit crabs to find. Lucky hermit crabs can move into these new dream homes.

    This year marks the 170th anniversary of Paul Gauguin's birth. He lived for just 54 years but he packed his brief life with activity.

    The French painter spent his early childhood in Peru before returning to France. As an adult, he continued to travel a lot. Most famously, he spent much of the last decade of his life in Tahiti, an island in southern Pacific Ocean. Indeed, Gauguin is best known for his colorful paintings of Tahitians and their culture.

    The restlessness of this great painter has been normal among modern artists since the middle of the 19th century. They're never satisfied for long with a certain style or way of life. Once something becomes conventional, it's turned down.

    The artistic culture that Gauguin developed from was that of Impressionism (印象派). Painters like Claude Monet had wanted to paint how they saw the world, not how their teachers taught them it should be seen. Gauguin, and similar artists like his friend Vincent van Gogh, moved even further away from "respectable" art than the Impressionists. For them, it was not simply a matter of seeing the world differently, but feeling and thinking about it differently, too.

    Gauguin saw, felt and thought differently from most members of European society. He thought that European culture was too fancy and not spontaneous. This is why he turned to the traditions of other parts of the world, like Africa, and, eventually, Tahiti. Artists like Gauguin used the word "primitive" for these cultures, but not as a negative term. For him, Europe, in becoming modem, industrial and scientific, seemed less natural than other parts of the world.

    In truth, Gauguin's paintings may be unconventional but they are certainly not "primitive". They are the work of a painter with great awareness of what he was doing. It was this awareness that made him such an important painter for those that came after, in the 20th century. When we look closely at the works of Gauguin we begin to understand Pablo Picasso, and especially Henri Matisse, a little better.

    The Largest World Fairs of All Time

    New York World Fair — New York, 1939

    The 1939 New York World Fair was the largest exposition (博览会) in US history with visitors over 14 million. The Fair was planned during the Great Depression and was aimed at relieving the city from economic depression by attracting foreign investment. Major inventions to emerge (出现) at the New York World Fair included nylon fabric, a streamlined pencil sharpener, and a futuristic car city imagined by General Moiors.

    Exposition liniverselle — Paris, 1900

    The Exposition Universelle was one of the earliest expositions to feature multiple countries with France inviting various countries to display their technological advancements and cultural heritage. Exposition Universelle was the birthplace of many inventions that we enjoy today including escalators (自动扶梯) and talking films.

    Expo' 70 — Osaka, Japan

    Expo' 70 was the biggest exposition of the 20th century and the second largest in history. Expo 70 had a record attendance of over 64 million visitors, a 40-year record that would not be broken until Expo 2010 in Shanghai. Notable exhibitions included a large piece of moon rock that was brought back from the Apollo 12 mission.

    Expo 2010 — Shanghai. China

    Expo 2010 goes down as the largest fair in history, having attracted 73 million people. It also had the highest international participation of any exposition in the world with 246 countries participating. The opening ceremony featured the biggest LED screen in the world as well as one of the biggest fireworks displays in history.