The African elephant, which is the largest land animal remaining on earth, is of great importance to African ecosystem. Unlike other animals, the African elephant is to a great extent the builder of its environment. As a big plant-eater, it largely shapes the- forest-and-savanna (大草原) surroundings in which it lives, therefore setting the terms of existence for millions of other animals that live in its habitat.

    It is the elephant's great desire for food that makes it a disturber of the environment and an important builder of its habitat. In its continuous search for the 300 pounds of plants it must have every day, it kills small trees and under-bushes, and pulls branches off big trees. This results in numerous open spaces in both deep tropical forests and in the woodlands that cover part of the African savannas. In these open spaces are numerous plants in various stages of growth that attract a variety of other plant-eaters.

    Take the rain forests for example. In their natural state, the spreading branches overhead shut out sunlight and prevent the growth of plants on the forest floor. By pulling down trees and eating plants, elephants make open spaces, allowing new plants to grow on the forest floor. In such situations, the forests become suitable for large hoofed plant-eaters to move around and for small plant-eaters to get their food as well.

    What worries scientists now is that the African elephant has become an endangered species. If the elephant disappears, scientists say, many other animals will also disappear from vast areas of forest and savanna, greatly changing and worsening the whole ecosystem.

    In England, people are fond of sport. In other words, lots of English people like the idea of sport and watch sport on TV. But the number who take part in sport is quite small. On the whole, English people prefer to be fat rather than be thin.

    The most popular sport in England is football. Football is played on Saturday afternoon in most towns and the supporters of a certain team will travel from one end of the country to the other to see their team play. There are four divisions(级别) of the football league. Not surprisingly the best teams are in the first division. But the best supporters are often in the fourth division. You have to be a good supporter to watch the fourth division football!

    Many other sports are also played in England, such as golf, in which you try to knock a ball into a hole; basketball, in which you try to get a ball through a net; tennis, in which you try to hit a ball so that your opponent(对手) can not hit it. As you see, if the ball had not been invented, there would have been no sport.

    Actually, that is not quite true. Athletics(田径) isn't played with a ball, nor horse-racing. Perhaps that is why they are not as popular as football!

    What would work be like if you had no boss?Imagine you could make all your own decisions and no one told you what to do.

    A Swedish software company,Crisp,decided to get rid of their CEO.First,they needed to find out what a CEO actually did.Then they shared those duties among staff and board members,which is exactly what they did.And the employees believes it's been a good change.An employee named Heinrik Kniberg says the company can now act faster,"If you want to get something done,you stand up and start driving that.Workers are also more active and satisfied."And any big decisions are made during the all-member meetings several times a year.

    So,if it's working well for Crisp,could this model become more widespread? Online retailer（零售商）Zappos tried out a similar plan but had unpleasant results.Almost a fifth of its staff decided to leave,and CEO Tony Hsieh admitted that "self-management is not for everyone".Mr Houston,founder of file-sharing service Drew Dropbox,says that total freedom doesn't always feel good,because you no longer know what you're supposed to do,what is important and you're bumping up against other people."

    Would you like to work somewhere with no boss?

    Scientists have always been interested in the high level of organization in ant societies. American researchers have watched ants build life-saving rafts to keep afloat during floods. They also have recorded how ants choose their next queen — the female whose job is to produce eggs.

    New technology is helping to improve researchers' understanding of the insects. But there is still a lot to be learned.

    Fire ants living in Brazilian forests are perfectly at home in an environment where flooding is common. To save themselves, the insects connect their legs together and create floating rafts. Some ant rafts can be up to 20 centimeters wide.

    David Hu is an engineer with the Georgia Institute of Technology, also known as Georgia Tech, saying, "If you have 100 ants, which means 600 legs, 99 percent of those legs will be connected to a neighbor. So they're very, very good at keeping this network. "

    David Hu and other Georgia Tech researchers wanted to study ants and the secret of their engineering. They froze ant rafts and then looked at them with the help of computed technology, or CT images. The pictures showed that larger ants serve in central positions to which smaller ants hold. The larger ants create pockets of air that keep the insects afloat.

    Scientists say small robots or materials that can change shape could be programmed in a similar way, working towards a shared goal.

    Researchers at North Carolina State University are also studying ants. They examined how Indian jumping ants choose the leader of the colony when they lose their top female or queen.

    No fashion event attracts the world quite like the Victoria's Secret Fashion Show. In November 2017, more than 55 models descended upon Shanghai for the lingerie（内衣）maker's first show in Asia. Victoria's Secret cast eight Chinese models for the show, including Liu Wen, double the number that walked in 2016.

    Liu Wen, a Chinese fashion model, started her modeline career in 2005 after competing in the reality TV show New Silk Road World Model Contest. Although she did not win the competition, Liu soon began working full-time as a model, eventually becoming a national success story after working with fashion magazines like Vogue and Harper's Bazaar that are popular in China, In 2007, she was signed to the Marilyn agency, and has since walked for Burberry. Givenchy, Chanel, Tom Ford, Proenza Schooler and Tommy Hilfiger.

    Liu walked a record 74 shows in New York, London, Milan and Paris for the autumn/ winter 2009 season, followed by 70 for spring/summer 2010, making her the second most-booked catwalk model that year. She has also achieved 15 international Vogue covers to date.

    In 2009, Liu became the first woman of Chinese origin to walk in the Victoria's Secret Fashion Show. Liu also participated in the 2010—2012 shows. She returned to the Victoria's Secret runway again in 2016.

    In the past, Liu has said that after modeling she might enjoy working as a stylist or, were the opportunity to arise, as an actress-she feels that modeling and acting have much in common, but for now she enjoys modeling and working in the fashion industry. She has stated that she knows that, as a career choice, working as a fashion designer or stylist would be “very hard work”, but she is now more seriously considering becoming a stylist because she would like “to share her fashion style -tomboyish, vintage, and comfortable-with the world”.

    Arthur Miller(1915-2005) is universally recognized as one of the greatest dramatists（剧作家） of the 20^th century. Miller's father had moved to the USA from Austria-Hungary, drawn like so many others by the “Great American Dream”. However, he experienced severe financial hardship when his family business was ruined in the Great Depression (大萧条时期) of the early 1930s.

    Miller's most famous play, Death of a Salesman, is a powerful attack on the American system, with its aggressive way of doing business and its insistence on money and social status as indicators (标志) of worth. In Willy Loman, the hero of the play, we see a man who has got into trouble with his system, Willy is “burnt out” and in the cruel world of business there is no room for sentiment (情绪): if he can't do the work, then he is no good to his employer, the Wagner Company, and he must go. Willy is painfully aware of this, and at a loss as to what to do with his lack of success. He refuses to face the fact that he has failed and kills himself in the end.

    When it was first staged in 1949, the play was greeted with enthusiastic reviews, and it won the Tony Award for Best Play, the New York Drama Critics' Circle Award, and the Pulitzer Prize for drama. It was the first play to win all the three of these major awards.

    Miller died of heart failure at his home in Roxbury, Connecticut, on the evening of February 10, 2005, the 56^th anniversary of the first performance of Death of a Salesman on Broadway.