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 anti­slavery 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 anti­slavery.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 slave­holding 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 black­face—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 that they did 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.

    David Beckham was born in 1975 in London, at a place called Leytonstone. When he was a young boy, his greatest passion was in football. He played it whenever he had the chance. Sometimes he would go and watch a game with his friends. When David Beckham was 12 years old, he won the Bobby Charlton Soccer Skills award. This was an important step forward for this young boy, and it led him to go for a visit to a football training camp in Spain. As a boy he played for schools of Essex and also for his county team.

    In 1991, he became a trainee with Manchester United. This meant that he could practice football as much as he wanted to and play for the highly successful Manchester United Youth Cup team and Under-21 team. In April, 1995 he played his first football league game against Leeds Untied. During 1995 and 1996, David became a regular member of the team and Manchester United won in both football seasons, with David scoring many goals.

    His goals made him a household name. In the first game of the 1996-1997 season, he scored a surprising goal from beyond the halfway line; seeing the goalkeeper a little way out of his goal, Beckham became famous overnight. He continued to score astonishing goals, especially from free-kicks. The speed of one of his shots was timed at 157 kph. He also had the ability to make the ball go from left to right, or right to left, whenever he chose. Goalkeepers were never sure where the ball was going, and it regularly ended up in the goal.

Why College Is Not Home

    The college years are supposed to be a time for important growth in autonomy(自主性) and the development of adult identity. However, now they are becoming an extended period of adolescence, during which many of today's students are not shouldered with adult responsibilities.

    For previous generations, college was a decisive break from parental control; guidance and support needed to come from people of the same age and from within. In the past two decades, however, continued connection with and dependence on family, thanks to cell phones, email and social media, have increased significantly. Some parents go so far as to help with coursework. Instead of promoting the idea of college as a passage from the shelter of the family to autonomy and adult responsibility, universities have given in to the idea that they should provide the same environment as that of the home.

    To prepare for increased autonomy and responsibility, college needs to be a time of exploration and experimentation. This process involves "trying on" new ways of thinking about oneself both intellectually(在思维方面)and personally. While we should provide "safe spaces" within colleges, we must also make it safe to express opinions and challenge majority views. Intellectual growth and flexibility are fostered by strict debate and questioning.

    Learning to deal with the social world is equally important. Because a college community(群体) differs from the family, many students will struggle to find a sense of belonging. If students rely on administrators to regulate their social behavior and thinking pattern, they are not facing the challenge of finding an identity within a larger and complex community.

    Moreover, the tendency for universities to monitor and shape student behavior runs up against another characteristic of young adults: the response to being controlled by their elders. If acceptable social behavior is too strictly defined(规定) and controlled, the insensitive or aggressive behavior that administrators are seeking to minimize may actually be encouraged.

    It is not surprising that young people are likely to burst out, particularly when there are reasons to do so. Our generation once joined hands and stood firm at times of national emergency. What is lacking today is the conflict between adolescents' desire for autonomy and their understanding of an unsafe world. Therefore, there is the desire for their dorms to be replacement homes and not places to experience intellectual growth.

    Every college discussion about community values, social climate and behavior should include recognition of the developmental importance of student autonomy and self-regulation, of the necessary tension between safety and self-discovery.

    Experts say there are about 6, 500 languages spoken throughout the world. But the United Nations estimates that about half of these languages are in danger of disappearing.

    One non-profit organization seeking to save world languages is a New York-based group called Wikitongues. Officials from Wikitongues say the organization has a simple goal: to provide the tools and support that people need to save their languages.

    Udell is the co-founder of Wikitongues. He said when a language disappears, many other things can go away as well. For example, parts of a community's culture, knowledge and identity can also be lost. Because of this. Udell believes the process of bringing languages back must be done by community members themselves, “from the ground up,” he said.

    “There is no way an outside organization can save someone's language for them.”

    Wikitongues was launched in 2016 as an open internet collection of world languages. The self-described “community” is operated by volunteers from around the world. The collection is in the form of language videos that people add to the Wikitongues website.

    There are currently more than 400 languages and dialects represented on Wikitongues' YouTube channel. Udell says more than 1,500 people from 70 different countries have added videos to the system.

    “We have people from India who record dozens of languages, which is beyond their own.” he said.

    One of Wikitongues'volunteers is Kolokwe, who lives in Namibia. His native language is Subiya, however, he does not get the chance to speak his native language every day. Like many other educated people from his area, he speaks a lot of English and Afrikaans.

    Kolokwe is hoping his involvement with Wikitongues call help keep Subiya and other African languages from going extinct. He wants the world to know about his language. But his goal goes beyond just sharing his language with others through video. He is also working to create a dictionary and language teaching materials that can be used in schools.

Earthworms don't move fast. But humans can accelerate the worms' spread. Fishermen often use invasive(蔓延性的) earthworms to catch fish. Many have introduced invasive earthworms to rivers, streams and lakes previously unexposed to these animals. Gardeners who use earthworms to make their soil rich may unknowingly introduce invasive ones. The worms even give rides in the mud on wheels, potted plants and road materials shipped around the nation.

But they're not everywhere yet. In the Great Lakes region, "20 percent of the land is earthworm-free," says Cindy Hale, a research biologist. Of the remaining 80 percent of land, half of the land has fewer than two earthworm species-meaning there isn't yet too much impact on the ecosystem, she explains. For these regions, she says, now is the time to take action. According to Hale, educating the public, especially fishermen, is one approach to stopping the spread of invasive earthworms. Identifying which lands are currently earthworm-free is another.

Ryan Huefimeier, a program coordinator for Great Lakes Wom Watch, has been working on a model that will help create large maps of areas with minimal(最小的) or no damage from earthworms. Ultimately, landowners can use it to identify earthworm activity on their property. once identified, lands with minimal or no earthworm damage should be protected.

But scientists suspect that once invasive earthworms arrive they can't be removed. And even if all could be, affected forests might never return to the way they were. "It's very much a story of learning to live with them," concludes Lee Frelich of the University of Minnesota's Center for Forest Ecology.

Forest ecologists have called earthworms "ecosystem engineers" because they can change or create habitats that otherwise would not be present. Whether this is a good thing depends on the situation.

"What the earthworms do and how we value it is what really matters." said Hale. "In one place-farm fields or gardens-we really like European earthworms and what they do, so we consider them good. In native hardwood forests, we really don't like what they do-so we consider them bad. You really have to understand how an organism(微生物) affects an ecosystem. Things aren't black and white."