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.

    Rachel Carson (1907-1964) is a writer, biologist, and environmentalist. As a trained scientist and a great writer, Rachel Carson did much to shape people's attitudes toward the natural world. Born in Springdale, Pennsylvania, she shared from childhood her mother's love of books and feeling for the beauty and mystery of nature. At Pennsylvania College for Women, she first majored in English, but later learned biology. The imagination of a creative writer with a scientific lobe for fact made her books successful. After graduating with honors, she won a scholarship to Johns Hopkins University, where she earned an A.M. in zoology.

    When her father died suddenly in 1935, she took a job as an aquatic(水生的) biologist. An article for the Atlantic Monthly led to her first book, Under the Sea Wind (1941). During World War II she wrote a series of booklets on wildlife refuges(收容所). Meanwhile she had been working on a book that would make her known throughout the world. Published in 1951, The Sea Around Us became an immediate best-seller, won many honors and literary awards, and was translated into thirty-two languages. After earning enough money, she could devote full time to writing. Her next book, The Edge of the Sea (1955), was also a success.

    Rachel Carson's last book, Silent Spring (1962), became one of the most famous books of the last half of the twentieth century. Ever since the end of World War II, when the insecticide (杀虫剂) DDT came on the market, she had been worried about the dangers in the uncontrolled use of the poisons: their effect on wildlife, on human life, and on the environment. She decided to speak out. The result was a book showing how modern society has been poisoning the earth on a worldwide scale. "A few thousand words from her," wrote a newspaper editor, "and the world took a new direction."

    Tickets for the 2014 World Cup in Brazil have gone on sale, with fans able to apply on FIFA's website. FIFA is expecting a similar demand to that in Germany 2006, when there were about seven applicants for every ticket of the 64 matches. And now around 3.3 million tickets will be available for the matches in 2014.

    Tickets will range in price from￡58 for first-round matches to￡632 for the final at Maracana Stadium in Rio de Janeiro. Brazilian citizens over 60, local students and members of some social programs can purchase tickets for ￡15.

    The Price of Football - World Cup 2014

    "It's always difficult to predict," said FIFA marketing director Thierry Weil. "But I truly believe that it will be more similar to what happened in Germany than in South Africa in 2010." According to FIFA, the 2006 World Cup was attended by more than 3.3 million fans. Almost two million tickets were sold to the general public in South Africa, although the number of applications during the first ticketing phase was significantly lower.

    All applications made before 10th October 2013 will enter a random selection draw if there are not enough tickets available to fulfill all requests. The sales of the leftover tickets will begin on 5th November on a first-come, first-served basis. Another phase（阶段） will begin on 8th December after the draw is made. The tournament begins on 12th June, with Brazil playing the opener in Sao Paulo.

    A study on the price of World Cup 2014 looked at the ticket prices and the cost of travelling to Brazil and found that our English fans face hotel costs of between￡46 and￡797 a night, while packages range from￡2,999 to￡14,999.

    When it's five o'clock, people leave their office. The length of the workday, for many workers, is defined by time. They leave when the clocks tell them they're done.

    These days, the time is everywhere: not just on clocks or watches, but on cellphones and computers. That may be a bad thing, particularly at work. New research shows that clock based work schedules hinder creativity.

    Clock-timers organize their day by blocks of minutes and hours. For example: a meeting from 9 a. m. to 10 a. m, research from 10 a. m to noon, etc. On the other hand, task-timers have a list of things they want to accomplish. They work down the list, each task starts when the previous task is completed. It is said that all of us employ a mix of both these types of planning.

    What, then, are the effects of thinking about time in these different ways? Does one make us more productive? Better at the tasks at hand? Happier? In experiments conducted by Tamar Avnet and Anne-Laure Sellier, they had participants organize different activities from project planning, holiday shopping, to yoga by time or to-do list to measure how they performed under "clock time" vs. " task time". They found clock timers to be more efficient(有效率的) but less happy because they felt little control over their lives. Task timers are happier and more creative, but less productive. They tend to enjoy the moment when something good is happening, and seize opportunities that come up.

    The researchers argue that task-based organizing tends to be undervalued and under-supported in the business culture. This might be a small change to the way we view work and the office, but the researchers argue that it challenges a widespread characteristic of the economy: work organized by clock time. While most people will still probably need, and be, to some extent, clock-timers, task-based timing should be used when performing a job that requires more creativity. It'll make those tasks easier, and the task-doers will be happier.

    SILVER SPRING, MARYLAND — Student engagement (参与) is a goal in schools everywhere. A teacher in the Washington suburbs has found a way to engage and motivate students — by ringing rhythm and fun to mathematics. The approach works well especially for students who speak English as a second language.

Making math fun

The voice heard in the video belongs to mathematics teacher Jake Scott. Most of the performers are his students. "I use rap because it is something that appeals to the students, and also because music aids memory," Scott explains.

    Scott started using rap videos three years ago. So far he has produced nine, including

Scott started using rap videos three years ago. So far he has produced nine, including YouTube favorites Triangle Experts and Quadratic Formulatic, which have been viewed tens of thousands of times. "It is fun and the whole process is something that students appreciate," Scott says.

    Empowering students

    Blair High School principal Renay Johnson is a big supporter. She even appears in Scott's latest video, Undefined Expressions.

"Mr. Scott is very motivating and engaging for students," Johnson notes. "He enjoys what he does. As you know he engages students and mathematics through music. But he is also our wrestling coach. He also sponsors National Honor Society. And he is also a director of after school sports academy. I am lucky to have him here as a teacher."

    Scott was recognized as an outstanding educator last year by the Montgomery County Council. He was also honored as 2011 teacher of the year by an African-American civil rights organization.

    Jake Scott says he wants mathematics to be something that students look forward to learning. And he says the results will help them on a path to college and a career.

    Stefano Boeri, the Italian architect, famous for his Bosco Verticale, a group of tree-covered skyscrapers in Milan, introduced his new plans to pioneer a similar project in the Chinese city of Nanjing.

    The Chinese version of Boeri's Bosco Verticale, or vertical forest, will be his first project in Asia. The project will consist of two neighboring towers that will be coated with 23 different species of trees and more than 2,500 kinds of bushes hanging down the sides of the buildings. The structures will be built with the ability to house offices and will feature a 247-room luxury hotel, as well as a museum and even a green architecture school. The towers are currently under construction and are set for completion within the next year.

    But two buildings aren't enough for the ambitious Boeri as he now has even bolder plans for China to create “forest cities” in a country that has become known as an urban center choking on poisonous gases and dust.

    In an interview about his plans to “greenify” the city and country Boeri said, “We have been asked to design an entire city where you don't only have one tall building, but you have 100 or 200 buildings of different sizes, all with trees and plants on the sides.” Boeri continued, “We are working very seriously on designing all the different buildings. I think they will start to build at the end of this year. By 2020 we could imagine having the first forest city in China.”

    Although these towers will lend a huge hand in decreasing air pollution in China's eastern city, Boeri has said, it will take more than a pair of tree-covered skyscrapers to really solve China's pollution crisis. This is why the Italian architect hopes to repeat his design in other parts of the country, as well as in other places around the world.