Since 1984,Philadelphia has been cleaning up its act.One by one,graffiti（涂鸦）covered walls are being changed into outdoor art.So far,more than 1,800 murals（壁画）have been painted.Philadelphia now has more murals than any other American city.

    The walls that were once ugly with graffiti are now covered with beautiful pictures of historical heroes and modern art, thanks to the Mural Arts Program(MAP).Its work makes schools and public places attractive,and its citizens very proud.The program began as part of Philadelphia's Anti-Graffiti Network.Jane Golden is the MAP's artistic director."When people ask me what our program is about,"she says,"I answer them with one word: hope." Each year, the MAP offers youth art programs and workshops.Some onetime graffiti writers even help paint MAP murals.

    The MAP's work,says Golden,is all about developing a sense of community（社区）.When a neighborhood requests a mural,the MAP works with the people there to develop a message.Some messages have been "Safe Streets,"Love and Care," and "Peace Walk".

    The MAP receives up to 50 requests for murals each week. Last year, the workers painted 140 murals."The making of a mural enters people's collective memory as an extraordinary, pleasant moment in neighborhood history," says Golden, who began as a muralist in Los Angeles.

    At UMOM New Day Centers, volunteers are the heart of our mission. We exist entirely through the generosity of individuals within the community. Through the giving of their time and talents, volunteers help homeless men, women and children find hope in the future.

    Child Development Center

    Type of help needed: Assist teachers with art projects, reading, singing, games and play projects for children aged one to five.

    Requirements: Ages 16+ only, must obtain an Arizona state fingerprint card, and must obtain a TB Test.

    Hours: Monday-Friday, 9:00am-12:00pm.

    T.A.P. (Teen Activities Program)

    Type of help needed: Assist TAP coordinator (协调员) with weekly activities. Coordinate and help with field trips, 5ports, cooking, music and other forms of entertainment. We welcome your ideas for teen activities,

    Requirements: Ages 21+ only, have graduated from high school, and must obtain an AZ state fingerprint card.

    Hours: Monday-Friday, 3:00pm-6:00pm and Saturday & Sunday 1:00pm-4:00pm.

    Summer hours: Monday-Friday 8:00am-4:00pm and Saturday & Sunday 1:00pm-4:00pm.

    In-Kind Donation Assistant

    Type of help needed: Moving, repairing, organizing furniture and other donated items.

    Requirements: Must be comfortable with physical labor, being outdoors, and be able to lift at least 50 lbs (磅).

    Hours: Tuesday-Saturday, 9:00am-3:00pm.

    Docent (讲解员)

    Type of help needed: Help screen visitors and volunteers and answer questions provide directions. Offer non-program-related assistance to residents to enhance customer service needed. Accept donations, event assistance and other projects as assigned.

    Requirements: Ages 18+ only, must obtain an AZ state fingerprint card, and be able to lift 50 lbs.

    Hours: Monday-Friday, l:00pm-4:00pm. Tuesday evening, 5:00pni-9:00pm.

    Saturday& Sunday, 9:00am-5:00pm.

    Kitchen Helper Program

    Type of help needed: Support kitchen staff in food preparation, serving and other duties as needed.

    Requirements: Volunteers must be 13 years and older to volunteer in the kitchen.

    Hours: Dinner: 7 days a week from 4:00pm-7:00pm;    Lunch: Monday Friday from 10:30am-1:00pm; Brunch: Saturday & Sunday from 9:30am-12:00am.

    Zoe Chambers was a successful PR (Public Relations) consultant (顾问) and life was going well—she had a great job, a beautiful flat and a busy social life in London. Then one evening in June last year, she received a text message telling her she was out of work. The first two weeks were the most difficult to live through.” she said. “After everything I'd done for the company, they dismissed me by text!I was So angry and I just didn't feel like looking for another job. I hated everything about the city and my life.”

    Then, Zoe received an invitation from an old school friend, Kathy, to come and stay. Kathy and her husband, Huw, had just bought a farm in north-west Wales. Zoe jumped at the chance to spend a weekend away from London, and now, ten months later, she is still on the farm.

    “The moment I arrived at Kathy's farm, I loved it and I knew I wanted to stay.” said Zoe.“ Everything about

my past life suddenly seemed meaningless.”

    Zoe has been working on the farm since October of last year and says she has no regrets. “It's a hard life, physically very tiring. ”she says. “In London I was stressed and often mentally exhausted. But this is a good, healthy tiredness. Here, all I need to put me in a good mood is a hot bath and one of Kathy's wonderful dinners. ”

    Zoe says she has never felt bored on the farm. Every day brings a new experience. Kathy has been teaching her how to ride a horse and she has learnt to drive a tractor. Since Christmas, she has been helping with the lambing-—watching a lamb being born is unbelievable, she says, “It's one of the most moving experiences I've ever had. I could never go back to city life now. ”

    Elephants are able to know the difference between a man and a woman, and can tell an adult (成年人) from a child—all from the sound of a human voice. This is according to a study in which researchers played voice recordings to wild African elephants.

    The animals showed more fear when they heard the voices of adult Masai men. Usually Masai people hunt elephants, and this suggests that animals have grown to listen for and avoid them.

    Prof. Karen McComb and Dr Graeme Shannon from the University of Sussex led the study. They explained that in former research they had used similar experiments to show that elephants could tell—from the sound of a lion—whether the animal was a female (雌性) or a more dangerous male (雄性).

    Prof  McComb wanted to find out if the animals used their very sharp sense of hearing to recognize danger from humans.

    The scientists recorded Masai men, women and children saying, in their own language, "Look, look over there, a group of elephants are coming." They also recorded Kamba men saying this phrase.

    Masai people often come across elephants, which can result in violent (暴力的) hunting. Kamba people, however, mainly feed on agriculture, which does not generally bring them into violent touch with the animals.

    When the team played recordings of these different voices through a hidden speaker, they found that elephant family groups showed more fear in response to the voice of a Masai man, than to a Kamba man's voice. And the adult male Masai voices caused far more violent response than the voices of women or boys.

    A telescope, called Gaia, is being designed by astronomers in Europe, and it couldn't be more different from Pan-STARRS, which is another telescope being designed. While Pan-STARRS will be looking for asteroids (小行星) and comets headed for Earth, Gaia will be looking at our entire galaxy (银河系).

    Gaia is designed to draw a map of the Milky Way, our home galaxy. Just as a map of your town gives you a picture of where things are located, Gaia's map of the galaxy will tell astronomers where the stars are. Over five years, Gaia will observe (观察) about a billion stars and other objects in our galaxy. Each object will be observed about 70 times.

    Gaia will be sent into space connected to a rocket. It contains two telescopes, each focused at a different angle (角度). These two telescopes act like Gaia's “eyes”. The reason why humans can see things in 3D is that we have two eyes focused on the same object, at slightly different angles. By using two telescopes like eyes, Gaia can produce the first 3D map of the positions of the stars it views.

    Gaia, which is to be sent into space, will be a powerful telescope. If you were to use it on Earth, for example, you could stand 600 miles away from your best friends and still get a clear picture of their hair.

    Gaia is one of more than a dozen telescopes being designed by scientists right now. The next generation of telescopes will reveal new parts of our universe that will seem surprising. The universe, with all its planets, stars and other strange objects, is a puzzle with pieces that we can see by using powerful telescopes.

    Mr. Brown was a writer. He wrote many books, and he thought they were quite good. He lived in the city. One morning, he went to a small town near the city to visit a friend. He went there by bus. When he got to the town, he saw a bookshop not far from the bus stop. As it was early, he decided to go in and have a look. There were many books in the shop. He was very happy that all the books in the shop were written by him. "Where are other writer's books?" he asked the man in the shop. The man looked up at him and answered. "Oh, they are all sold out."