The African elephant, the largest land animal remaining on earth , is of great importance to African ecosystem(生态系统). 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(栖息地).

    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 underbushes, 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.

    When you're on the go, your best friend and resource can be your phone. In the age of smart phones, apps are like guiding stars: They can point you in the right direction for a hotel, list expenses, send postcards, and much more. When used together, these apps can be the basic travel tool, placing a wealth of information at your fingertips no matter where you are on the planet. U.S. NewsTravel has picked the essential travel apps, known for their utility and reliability. Best of all, they cost absolutely nothing.

Trip It

    Your Personal Travel Agent

    Be your own travel agent and plan every detail of your trip—from car rental to accommodating restaurants—with Trip It. You can make travel schedule by hand, or simply forward the email confirmations of your flight, rental car, train tickets, and hotels to plans.

Weather Free

    Your Go-To Meteorologist(气象学者)

    Stop trying to explain the weather forecast on the evening news (particularly when it's in a foreign language). The Weather Free app informs you (in English) of the climate in various locations. It features the local weather, and other key factors that will inform your decision about what to wear before stepping outside.

Goby

    Your Event Guru

    When you're in a foreign city, you sometimes look around and ask: Where are all the people? Goby has the answer. This app pinpoints the neighborhood hot spots (including museums, hotels, eateries, and more) in your neighborhood. But its true value comes in finding nearby events. You'll discover concerts, plays, and more right around the corner.

    At times my mom has been uncomfortable seeing these qualities in me. For example, when I was 12, I went to Puerto Rico all by myself to stay with my grandmother for the summer. My mom was extremely nervous about it. She kept telling me how things were different in Puerto Rico, to always put on sunscreen， not to wander away from my grandmother, and other warnings. She helped me pack and did not leave the airport until she saw my plane take off.

    But despite her worries, she let me go on my own. As I moved into my teens, she continued to give me space to grow and learn, even when it might have been difficult for her. When I reached my senior year, I decided to move away for college. Once again I found that I differed from my peers. While many of them wanted to stay close to home, I couldn't wait to be out in the world on my own. While my mom may not have been happy at the thought of my going away, she was supportive and excited for me.

    One big thing I realized during my senior year, as my mom granted me more freedom, was that she actually believes in me and trusts me. That means a lot. Most of my life, and especially when I was little, the main person I tried to impress in my schoolwork or other things was my mother. I knew she expected nothing but the best from me. Sometimes it was hard to live up to her standards: getting a single B on my report card would make me feel bad because I knew she wanted me to have all As.

    I know that her high standards have helped me stay focused on what's important, like education, and made me who I am. I am thankful for her support and involvement in my life. Most of all I respect her. She is the strongest woman I know and that's why I have turned out so strong and independent.

    I come from a large family of nine brothers and sisters, and all of us have kids of our own. On each Christmas night, our entire family gathers at my oldest sister's home, exchanging gifts, watching the nativity skit put on by the smaller children, eating, singing and enjoying a visit from Santa himself.

    The Christmas of 1988, my husband Bob and I had four children. Peter was eleven, Leigh-Ann was nine, Laura was six and Matthew was two. When Santa arrived, Matthew parked himself on Santa's lap and pretty much remained dazzled by him for the rest of the evening. Anyone who had their picture taken with Santa that Christmas also had their picture taken with little Matthew.

    Little did any of us know how precious those photos with Santa and Matthew would become. Five days after Christmas, our sweet little Matthew died in an accident at home. We were lucky to have strong support from our families and friends to help us through. I learned that the first year after a death is the hardest, as there are so many firsts to get through without your loved one. Birthdays and special occasions become sad, instead of joyous.

    When our first Christmas without Matthew approached, it was hard for me to get into the holiday spirit. Bob and I could hardly face putting up the decorations or shopping for special gifts for everyone. But we went through the motions for Peter, Leigh-Ann and Laura. Then, something extraordinary happened to raise our spirits when we didn't think it was possible.

    We were just finishing dinner when we heard a knock on the front door. When we went to answer it, no one was there. However, on the front porch was a card and gift. We opened the card and read that the gift-giver wanted to remain anonymous; he or she just wanted to help us get through a rough time by cheering us up.

    In the gift bag was a cassette of favorite Christmas music, which was in a little cardboard Christmas tree. The card described it as being "a cartridge in a pine tree," a twist on the "partridge in a pear tree" verse in the song, "The Twelve Days of Christmas." We thought that it was a very clever gift, and the thoughtfulness of our "elf"(精灵) touched our hearts. We put the cassette in our player and, song by song, the spirit of Christmas began to warm our hearts.

    That was the beginning of a series of gifts from the clever giver, one for each day until Christmas. Each gift followed the theme of "The Twelve Days of Christmas" in a creative way. The kids especially liked "seven swans a-swimming," which was a basket of swan-shaped soaps plus passes to the local swimming pool, giving the kids something to look forward to when the warm days of spring arrived. "Eight maids a-milking" included eight bottles of chocolate milk, eggnog and regular milk in glass bottles with paper faces, handmade aprons and caps. Every day was something very special. The "five golden rings" came one morning just in time for breakfast — five glazed doughnuts just waiting to be eaten.

    We would get calls from our family, neighbors and friends who would want to know what we had received that day. Together, we would chuckle at the ingenuity and marvel at the thoughtfulness as we enjoyed each surprise. We were so caught up in the excitement and curiosity of what would possibly come next, that our grief didn't have much of a chance to rob us of the spirit of Christmas. What our elf did was absolutely miraculous.

    Each year since then, as we decorate our Christmas tree, we place on it the decorations we received that Christmas while we play the song "The Twelve Days of Christmas." We give thanks for our elf who was, we finally realized, our very own Christmas angel. We never did find out who it was, although we have our suspicions. We actually prefer to keep it that way. It remains a wondrous and magical experience - as mysterious and blessed as the very first Christmas.

The Ig Nobel awards are usually known as the "Igs" and are given out every year at around the same time as the real Nobel awards. The "Igs" are given for achievements that "make people laugh, and then make them think". The name "Ig Nobel" is a language joke. "Nobel" sounds like "noble" -- meaning "very honored". And Ig Nobel sounds like "ignoble" meaning the opposite of noble — that is, "not honored"

    According to Marc Abrahars, who co-founded the award in 1991, "Most prizes, such as Nobel Prize, reward the goodness of the people who receive them. These prizes are meant to honor the extremes of humanity-those whose achievements should be seen as very good."

    "The Ig Nobel Prize isn't like that. The Ig honors the great confusion in which most of us exist much of the time. Life is confusing. Good and bad get all mixed up. If you win an Ig, it shows that you have done something. What that thing is may be hard to explain. But the fact is, you did it, and have been recognized for doing it."

    The Nobel science prizes encourage us to think that all over the world great discoveries are being made that will do good to the whole world. But real science is not like that. The main job of science is to find out what is not true. This leads people into areas of research that seem completely senseless. Why did a team of Japanese scientists spend months trying to teach birds to enjoy the paintings of Picasso? Why did a Norwegian biologist start a project to encourage insects to drink beer? It is hard to say. But it won them all an Ig.

    Sometimes science tells us things that we don't want or need to know. We don't want to know that falling in love and going mad are exactly the same as far as the brain is concerned. And we don't really need to know that worrying about money can cause tooth disease. Only the Ig award brought these great achievements to our attention.

Dear Mr.ing,

    I'm Bob Watson, one of the customers in your grocery store. I'm writing to express my idea about your goods.

    Your Supermart is outstanding in many ways. First I enjoy the selection of produce and fresh bakery items. Second your low prices and excellent customer service keep me coming back to Supermart. I have found, however, that I must make a separate shopping trip to one of your competitors because there are many items your store does not carry. This becomes inconvenient for me, as my time is valuable, and I don't like to make two trips. I have been a long time Supermart shopper and hope to continue for many years. If I could find all the items I need in one place, I would be a more satisfied customer.

    Specifically, I have never been able to purchase nacho cheese soup at your store. I can find other flavors (味道) of soup, but your store does not carry nacho cheese soup, a common ingredient (原料) in many of my recipes. In addition, I can only find large wonton wrappers, while many other stores carry both large and small and offer a more varied selection for their customers. Another example is Regent Brand Chili Seasoning. Though it is not a leading brand, it is still common on the shelves of other grocery stores in this area and is superior in flavor to its competitors.

    I sincerely hope to continue a relationship with your store, and I hope that you will consider the possibility of expanding your goods to be more competitive.

Yours truly,

Bob Watson