Experiments under way in several labs aim to create beneficial types of genetically modified foods, including starchier potatoes and caffeine-free coffee beans. Genetic engineers are even trying to transfer genes from a cold-winter fish to make a frost-resistant tomato.

    A low-sugar GM strawberry now in the works might one day allow people with health problems such as diabetes (糖尿病) to enjoy the little delicious red fruits again. GM beans and grains rich in protein(蛋白质) might help people at risk of developing kwashiorkor. Kwashiorkor, a disease caused by severe lack of protein, is common in parts of the world where there are severe food shortages.

    Commenting on GM foods, Jonathon Jones, a British researcher, said: "The future benefits will be enormous（巨大的）, and the best is yet to come". To some people, GM foods are no different from unmodified foods. "A tomato is a tomato," said Brian Sansoni, an American food manufacturer.

    Critics of GM foods challenge Sansoni's opinion. They worry about the harm that GM crops might do to people, other animals, and plants.

    In a recent lab study conducted at Cornell University, scientists tested pollen(花粉) made by BT corn, which makes up one-fourth of the U.S. corn crop. The scientist dropped the pollen onto milkweed, a plant that is the only known food source of a butterfly caterpillar(毛虫). Within four days of feeding on the leaves, almost half of a test group of caterpillars died. "This is a warning bell." said Cornell researcher Linda Raynor.

    Some insects that are not killed by GM foods might find themselves made stronger. How so? The insecticides are used on the crops to kill the pests. But GM plants produce a continuous level of insecticide. Insects relying on those crops may develop resistance to the plants and they may also develop a resistance to the insecticide.

    At the forum on GM food held last year in Canada. GM crops that have been made resistant to the herbicide might crossbreed with wild plants, creating "superweeds" that could take over whole fields.

    So where do you stand? Should GM food be banned in the United States, as they are in parts of Europe? Or do their benefits outweigh（胜过） any of the risks they might carry?

    First, I want to tell you how proud we are. Getting into Columbia shows what a great well-rounded student you are. Your academic, artistic, and social skills have truly blossomed（开花）in the last few years. You have become a talented and accomplished young woman. You should be as proud of yourself as we are.

    College will be the most important years in your life. It is in college that you will truly discover what learning is about. I want to tell you: “education is what you have left after all that is taught is forgotten”. What I mean by that is the materials taught isn't as important as you gaining the ability to learn a new subject, and the ability to analyze a new problem. That is really what learning in college is about—this will be the period where you go from teacher-taught to master-inspired, after which you must become self-learner.

    Follow your passion in college. Take courses you think you will enjoy. Steve Jobs says when you are in college, your passion will create many dots, and later in your life you will connect them. In his great speech given at Stanford, he gave the great example where he took calligraphy（书法）, and a decade later, it became the basis of the beautiful letters in Microsoft Word. So don't worry too much about what job you will have, and don't be too utilitarian（功利的）, and if you like Japanese or Korean, go for it! Enjoy picking your dots, and be assured one day you will find your calling, and connect a beautiful curve through the dots.

    Most importantly, make friends and be happy. College friends are often the best in life, because during college you are closer to them physically than to your mom and I. Pick a few friends and become really close to them-pick the ones who are honest and sincere to you. Don't worry about their hobbies, grades, looks, or even personalities. You have developed some real friendships in high school in your last two years, so trust your instinct, and make new friends.

    College is the four years where you have the greatest amount of free time, the first chance to be independent, the most possibilities to change and the lowest risk for making mistakes. So please treasure your college years! May Columbia become the happiest four years in your life, and may you blossom into just what you dream to be.

    One day a little boy, annoyed by his father's decision for him to become a grocer, decides that he will never grow up. Grocery is a dull job and staying a child is his protest against it. This strange little boy-man, never separated from a tin drum he is always banging, is our hero of the table. It covers three crucial decades of 20th century history. Little Oscar Matzerath will experience love, war and imprisonment in a story that paints an unforgettable picture of Central Europe between 1923 and 1954.

    This is an overview of the story of The Tin Drum, the most famous work by the German Nobel-winning author Günter Grass, who passed away on April 13 at the age of 87. The Tin Drum also established Grass as one of the leading authors of Germany. It also set a high bar of comparison for all of his following works. Just as his best-known fiction is both the story of an individual and of an age, so it is that Grass' life cannot be understood without referring to the history of Germany. He was called "Germany's conscience", because he reminded Germans of a past during the Second World War (1933-1945) that many would have rather forgotten.

    This sometimes made him unpopular. Many Germans did not agree in 1989 when he said that East Germany and West Germany should remain separate, as a united country would be too strong and threaten the world's peace. And Grass was called a hypocrite when he revealed in his memoir

    Peeling the Onion (2006) that he had been a teenage member of the Waffen-SS, the Nazi (纳粹) Party's fighting force. The man who had blamed the actions of others had a less-than-perfect record himself.

    Grass was a man of the pen and the page and also a man with a gift for speaking to the public.

    His writing was noisy and annoying, but one had to listen to it, a little like the sound of the drum banged by his most famous literary creation.

    JERUSALEM—Israel's Environmental Protection Ministry asked citizens Wednesday to avoid unnecessary physical activity and stay indoors, as a serious sandstorm struck the Middle East in a thick yellow haze (霾) for a second day with no hope to see things clearly.

    The ministry said heavy levels of dust and sand in the air were a threat to cities throughout the country. The ministry's website advised pregnant women, the elderly and those with heart and respiratory (呼吸的) conditions to stay indoors, and asked schools to keep children indoors.

    The emergency service Magen David Adom reported that it has treated more than 300 Israelis suffering from breathing problems, and that hospitals have more respiratory-related patients, including a large number of the elderly and those with asthma and related conditions.

    The domestic Israeli airlines Arkia and Israir continued to ground their flights to Eilat because of reduced visibility.

    The sandstorm has affected Egypt, Jordan, Iraq, Lebanon and Syria, where at least five deaths have been reported.

    "There has been nothing that came close to the magnitude of this sandstorm," said Daniel Rosenfeld, a professor with the Institute of Earth Sciences at the Hebrew University in Jerusalem.

    "While Israel has experienced a number of sandstorms in the past, they started from the Sinai Desert and the Sahara Desert to the south and were joined by winter windstorms that cleared the air," he said. In this case, the storm comes from Syria and Iraq to the north and east.

    Because the storm is hitting during the summer, at a time of both little wind and severe heat and humidity, forecasters expect the particles to remain in the air throughout the weekend and possibly into next week.

    "This is really puzzling," said Rosenfeld, adding that he and his colleague will conduct research into the origins of the unprecedented (前所未有的) storm. (326 words)

    Bike sharing have become popular words in cities from Cape Town to Shanghai to Melbourne. Planners, politicians and media keep showing off their benefits: reducing pollution, congestion, travel costs and oil dependence, while improving public health. Bike sharing also helps make cities appear modern, dynamic and worldwide--qualities much sought after by the creative class.

    But what makes for a successful public bike-sharing program? This is an important question because installing one requires significant public and private investment and adjustment to the built environment.

    While many programs have been launched among much praise, often their popularity has soon declined. Many end up operating at a financial loss and depend on other profitable enterprises to cross-subsidize (交叉补贴) them. Some have resulted in thrown-away bikes becoming an eyesore.

    Understanding which factors enhance or stop public bike sharing is critical in helping cities decide whether such a program is workable, before considering what design and sitting will work best.

    Drawing on current knowledge, we discuss the importance of the local landscape, climate, cycling infrastructure (基础设施) and land use. We also touch on other factors, such as the legal environment and the characteristics of the bike-sharing program itself.

    Take natural environment for example. Two natural environment factors are known to affect participation: hilliness and weather. Hilliness discourages balanced bike-sharing use, as users avoid returning bicycles to stations on hilltops. Those stations end up being empty, while stations on flat areas are often full, so users cannot find a station to return their bikes.

    As for weather, ideal temperature ranges vary by the climate zone. Case studies show warm and dry weather encourages public bike-sharing use. Rain and strong wind reduce the frequency of trips. However, some approaches, such as providing sheltered, shaded, or even heated or cooled cycling infrastructure, could prove useful.

    A young woman turns around and around quickly, and jumps high. In the background, a young girl reads a rejection (拒绝) letter from a ballet school. "You have the wrong body for ballet," it says, "and at thirteen, you are too old." This was one of the most popular advertisements (广告) of 2014 and it describes American ballet Theatre's principal (主要的) dancer Misty Copeland.

    This was not a real letter. But Copeland says it is very similar to letters from her childhood. While many dancers start at the age of three. Copeland only began to study ballet in 1995 as a thirteen-year-old.

    People often told her that she was too old, or that she didn't have the perfect body type (She is only 157 cm tall). Her family moved a lot, and it was sometimes difficult for her to attend ballet classes. But Copeland loved dancing and did not want to give up. She stayed with her ballet teacher during the week and spent time with her family only at the weekend. This was a difficult life, but she worked hard and won her first national competition when she was fourteen years old. Copeland joined the American Ballet Theatre in 2000 and performed in many ballets over the next few years. In 2007, she became a solo (单独的) performer, and in 2015 she became its principal dancer.

    Copeland is now a dancer, author and Broadway performer. She also stars in the 2015 film A Ballerina's Tale. So what's next? According to Copeland, anything is possible: "My career (职业) really is just now beginning."