Green is an important color in nature. It is the color of grass and the leaves on trees. It is also the color of most growing plants.

    Sometimes, the word green means young, fresh and growing. Sometimes, it describes something that is not yet ripe or finished. For example, a greenhorn is someone who has no experience, who is new to a situation. In the fifteenth century, a greenhorn was a young cow or ox whose horns(角) had not yet developed. A century later, a greenhorn was a soldier who had not yet had any experience in battle. By the eighteenth century, a greenhorn had the meaning it has today—a person who is new in a job.

    Someone who has the ability to grow plants well is said to have a green thumb. The expression comes from early nineteen hundreds. A person with a green thumb seems to have a magic touch that makes plants grow quickly and well. You might say that the woman next door has a green thumb if her garden continues to grow long after your plants have died.

    The Green Revolution is the name given some years ago to the development of new kinds of rice and other grains. The new plants produced much larger crops. The Green Revolution was the result of hard work by agricultural scientists who had green thumbs.

    Green is also the color used to describe the powerful feeling, jealousy(嫉妒). The green-eyed monster is not a frightening creature from outer space. It is an expression used about four hundred years ago by British writer William Shakespeare in his play “Othello”. It describes the unpleasant feeling a person has when someone has something he wants. A young man may suffer from the green-eyed monster if his girlfriend begins going out with someone else. Or, that green-eyed monster may affect your friend if you get a pay rise and he does not.

    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.

    Do you have any foreign friends? Do you know their characteristics(特征)?

    The Germans are very quiet and they always keep calm. They don't like to speak many words. They look very serious. They like different kinds of amusements. The Germans are very hard-working. They like tidiness, especially the women, who always keep their home clean.

    In some ways, the Englishmen look the same as the Germans. They are very quiet and never talk too much with the strangers. They are really polite, so we often hear they say “Thank you.” or “Sorry.” The gentlemen are also the Englishmen.

The French's holidays are very long. They like traveling and usually spend their long time on staying in other countries. The Frenchmen are more outgoing than the Germans. It is very easy to make friends with them.

    Compared to the Frenchmen, the Americans are more outgoing. And they are even opener than all of the Europeans. They don't like to depend on others. So it is very common that the students do part-time jobs in their free time. And in Americans' eyes, success is an important part in their life.

    My father was attached to gardening by birth. One of my earliest memories is following Dad barefoot around in the garden with both hands blackened from digging in the soil. The garden was a wonderland full of possibilities.

    As Dad grew older, he still loved gardening. Even when he was diagnosed with cancer, he still planted all sorts of plants. Sometimes, I would come over to visit, and we would walk together in the garden. But then, something changed. Like the weeds that took over his garden, the cancer grew rapidly in Dad, and the doctor gave up. I stayed with Dad twenty-four hours a day and I found myself in all kinds of uncomfortable situations with Dad until I promised to care for the garden.

    Though I had heard the words of the doctor, what really made me believe that Dad was dying was the state of his garden. That year, he only planted tomatoes. Too tired to weed them, he simply tied them with strong strings to the fence and let them be. It made me sad to see them ignored, so I would come over and water them once in a while, and remove the weeds. I still remember the day I picked the last tomato from the vine(藤). That day was one of the saddest I had ever experienced in my life.

    Three years ago, I decided to plant my own garden. I decided I would start out with just a few tomatoes. That morning when I moved to the garden, something caught the corner of my eye and I had to smile. It was my eight-year-old son Nathan, standing barefoot in the soil, happily playing in soil.

    A lifetime of active exercise will let you keep the body of a 20-year-old well into your 70s, scientists have found.

    The physical decline (衰退) thought to be an unavoidable part of ageing is actually the result of not exercising enough, according to the research, which found that regular cyclists kept the muscles, lungs, and even the immune system (免疫系统) of people years younger. Besides, many serious health problems could be prevented if people became more active, researchers insist.

    Janet Lord, a leading researcher, said, “Our findings prove the false belief that ageing automatically makes us weaker. We now have strong evidence that encouraging people to do regular exercise throughout their lives can solve the problem that we are living longer but not healthier.”

    She looked at 125 cyclists aged 55 to 79 who had been exercising regularly for 25 years and compared them with 75 ordinary people of a similar age and 55 people aged 20 to 36. On a series of physical measures, the cyclists showed no difference from people much younger in their immune systems and making T cells.

    Now Professor Lord aims to discover how much exercise people need to do to stay young. “You needn't work out a lot. It may be intensity (强度) that helps—like going up and down the stairs ten times a day.”

    While there is no magic method of staying mentally and physically fit in later life, the benefits of keeping active can never be ignored, whatever your age or state of health.

    If you make a list of the top ten most challenging jobs in the world, chances are that being a teacher will not make the cut. Let's think about their complex task millions of educators face each day as they try to teach a group of often unfriendly, disorderly kids into intelligent, well-rounded individuals. That surely has to be the toughest job in the world, especially taking into consideration that there is no promotion waiting for them even if they are wildly successful!

    What if these all-important individuals that we often take for granted disappear from our lives? That was what Project Ed and Participant Media's teaching campaign asked filmmakers of all ages to envision for their recently-held contest.

    Their short films were called "A World without Teachers", whose intention was to inspire more young people to become teachers. However, the 62 amazing video submissions (提交物) also serve as a reminder of how terrible things would be if we didn't have these selfless individuals guiding us through life. What was interesting is that even the youngest contestants didn't accept the idea that there's no person to tell them what to do.

    High-school student Savannah Wakefield considered if art as we know today would have been different without teachers. Would C. Monet have discovered his talent for impressionism?

    Miles Horst won the 1,000-dollar prize for the best adult submission, lie pictures n world where teachers are replaced by a "brain box". Youth group winner Marina Barham's video describes a fact we all know but often forget. Teachers don't just teach; they inspire—something that no electronic device, no matter how smart, can do!

    So the next time you think your teacher is being "troublesome" for trying to channel you in the right direction, imagine a life without him/her.