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.

The idea of being able to walk on water has long interested humans greatly. Sadly, biological facts prevent us ever accomplishing such a thing without artificial aid—we simply weigh too much, and all our mass pushes down through our relatively small feet, resulting in a lot of pressure that makes us sink.

    However, several types of animals can walk on water. One of the most interesting is the common basilisk Basilicus basilicus, a lizard (蜥蜴)native to Central and South America. It can run across water for a distance of several meters, avoiding getting wet by rapidly hitting the water's surface with its feet. The lizard will take as many as 20 steps per second to keep moving forward. For humans to do this, we，d need huge feet that we could bring up to our ears in order to create adequate w hitting.

    But fortunately there is an alternative : cornflour. By adding enough of this common thickening agent to water (and it does take a lot), you can create a “non-Newtonian” liquid that doesn't behave like normal water. Now, if the surface of the water is hit hard enough, particles(粒子）in the water group together for a moment to make the surface hard. Move quickly enough and put enough force into each step, and you really can walk across the surface of an adequately thick Liquid of cornflour.

    Fun though all this may sound, it's still rather messy and better read about in theory than carried out in practice. If you must do it, then keep the water wings handy in case you start to sink--and take a shower afterward!

    On a cool morning, Wilson Kasaine heads out along a dirt path in southern Kenya. His calmness makes it easy to forget that he's tracking one of the most dangerous animals in the world. Kasaine is tracking lions—especially one lion called Marti, who is the real-life Lion King of Selenkay Conservancy.

    Tracking lions on foot may sound like a death wish, but Kasaine has been doing it for most of his life. Born into a traditional Maasai family he quickly grew to understand the beauty and danger of wildlife. Living with big wild animals forces him to develop a good sense of where they have been and where they may be going. During his 12-kilometer walks to and from school, he learned how to tell the paw prints (爪印)of a lion from those of other animals.

    Growing up, Kasaine knew that improving his tracking abilities would help him avoid surprise meetings with dangerous animals. For many Maasai, tracking is mainly a matter of self-protection. But Kasaine is tracking lions to meet them and to protect them. He leads a small group of wide-eyed tourists over the red sandy path, searching for the lion that has left upon it his prints.

Each year, thousands of tourists crowd Kenya's national parks to try to have a look at the"big five”; elephants, rhinoceros, leopards, buffaloes and lions. The international draw of these animals matters a lot because the nation's economy is tied to the protection of its wildlife. If Kenya's wildlife disappears, so does its second-largest source of income.

    Wildlife protection efforts in Kenya meant marking off land exclusively(专门地)for animals. But it also meant that the people who had originally lived in the area were forced to leave their land and into smaller surrounding areas. They are also finding it increasingly hard to keep a traditional Maasai lifestyle. But people are glad that it really makes a difference to wildlife protection.

    It was another frustrating day. I came home from school, changed my clothes and got ready for work. I worked at a local restaurant in town.

    I went to work feeling down. It's the same thing over and over again, dealing with customers who complain about their food—how the piece of pie that they are served is too big or too small. Three elderly ladies walked in and sat by the windows. I was working since 5:00 pm. and we were quite busy. But these elderly women were watching me as I was working really hard to make sure every table was clean and ready for the next customers.

    When they were finished with their meals, I took their plates back to the kitchen. They talked to me for a while about school, how I was doing, which grade I was in and what I planned to do in the future.

    As they were leaving, they walked past me and one of them said to me in a confident and gentle voice, "You are going places." They left the restaurant and I was pretty much in awe. I had tears in my eyes, because they gave me a reason to believe in myself. They picked my spirits up from being down and out and gave me a reason to keep on working hard and to give it my all.

    Imagine yourself on a boat looking out at the horizon and all you can see is the water meeting the sky with no land in sight and you are sailing straight ahead to meet the world. Jesse Martin does not have to imagine: he is living in it.

    On Dec. 7, 1998, at 17 years old, Jesse set sail from Melbourne, Australia on his boat, attempting to become the youngest person to sail alone and nonstop around the world. He sailed south of New Zealand, through the South Pacific, around South America, north on the Atlantic, back south past Africa, through the Indian Ocean and back to Melbourne. Even as a young child, Jesse had been an adventurer who traveled all over Europe and Asia with his parents. Born in Munich, Germany in 1981, he moved to Australia with his family when he was only two years old. They moved close to a rainforest in Cow Bay, about 3, 500kms north of Melbourne, where they built a small house with no electricity or running water. Jesse grew up at the beach enjoying the outdoors to its fullest. At 14, he sailed for the first time with his father and brother, Beau. It was after this trip that he began to dream about sailing around the world.

    Jesse's family played an important role. "I was made to believe I could do anything, although there were others that were not so encouraging or supportive" he says. "People that I looked up to, respected and trusted told me I couldn't. Thankfully, I trusted myself. There were people that said that the boat couldn't be ready by the time I had to leave." However, through perseverance (坚持不懈) and belief in himself, he was able to do what many told him was impossible.

    On Oct.31, 1999, more than 10 months after he set sail, Jesse Martin went down in history as the youngest person to sail around the world alone, nonstop and unassisted.

Having a great collection of books at home doesn't really mean that you are a person who has a passion for literature and reading. It can be a family inheritance (继承) or it can be just to impress people around you about the fact that you are a person of culture. On the other hand, there are many persons who cannot afford to buy books, because some of them are quite expensive, but they usually go to libraries and spend hours reading something that interests them a lot, or just borrow books to read at home.

From my point of view, literature is very important in our lives from several points of view. For example, reading is a means of gaining culture and enriching our knowledge in different areas of activities. It can help us have a great imagination and it makes things easier when it comes to making compositions on different themes. It gives you the possibility to speak about science, even if you don't work in this field, or you can express your opinion about a political aspect, just because you have read something connected to that.

Secondly, literature offers us the possibility to enter the world of imagination, and to leave apart the real one for a couple of hours. We come to meet kings and queens many years ago, dream in the world of the rich or imagine how life will be in the future. Sometimes, we identify ourselves with the characters in the stories we read and they can give us some clues to solve our problems and how to react in certain circumstances.

To conclude, I would like to say that literature is the perfect means to enrich our culture, to express correctly and have a rich vocabulary, to be able to interfere (干涉) in conversations in different fields of interest and to really be considered an erudite person.