Today, the world's diversity (多样性) of food crops is quickly decreasing. But scientists around the world are taking action. They are building seed banks. At seed banks, scientists store the seeds of many different crops.

    There are now 1,400 seed banks around the world. However, some banks are in warm countries. If the electricity fails, the seeds will get too hot and die. Other seed banks are in countries troubled by war. Sometimes people damage the seed banks. If this happens, valuable seeds can be lost forever!

    The organization Global Crop Diversity Trust decided they wanted to deal with this problem. So, they decided to build a global seed bank. This seed bank would contain a back-up, or extra copy, of all the world's seeds. Smaller seed banks would still collect and keep local seeds. But they would also send copies of their seeds to the global bank.

    Scientists from the Global Crop Diversity Trust chose the cold, snowy mountains of Svalbard, Norway to build the global seed bank — the Svalbard Global Seed Vault (斯瓦尔巴全球种子库). Organizations, farmers, or local seed banks store their extra seeds there. And the people who place their seeds in the vault are the only people who can take them out. They pay to ship their seeds to Norway, but it does not cost them any money to store their seeds. The Global Crop Diversity Trust pays for this.

    Cary Fowler is a scientist who heads the Global Crop Diversity Trust. He said, “If the Seed Vault simply supplies seed banks with copies of seeds that those banks lost by accident, the Seed Vault will be worth more than it cost.”

    Long ago，poems were recited out loud instead of being written down. Back when the Greeks first started the Olympics, they held poetry contests as well as athletic competitions.

    Now，poetry competitions have been revived (恢复). This year 120,000 high school students competed in the first Poetry Out Loud national recitation contest，performing poems from memory for $100,000 in prizes.

    The first competitions were held in classrooms. The winners went on to school－wide contests, and then they competed in city and state competitions. Finally, the 50 state champions，along with the District of Columbia champion came to Washington D．C．last week for the last showdown. After the 51 champions competed against one another, 12 went on to the finals. Then the field was narrowed to five. The final five had one last chance to “perform” a poem. The overall champ, Jackson Hille, a high school senior from Ohio, won a $20,000 scholarship.

    The National Endowment for the Arts and the Poetry Foundation started Poetry Out Loud, because they realized that bearing a poem performed is a different experience from reading it on a page.

    It's not just a matter of saying the words in the right order. It's the tone of voice, the pauses, the gestures and the attitude of the person performing that bring the words to life. “Each time we hear somebody recite a poem, we understand again what we found fresh and interesting about it，” said National Public Radio Broadcaster Scott Simon, master of ceremonies for the finals. Hearing it in a new voice offers something new to the listener.

    Not only do the people hearing poems have a new experience, but memorizing and presenting poems helps the participants (选手) understand those poems in a new way. Another benefit of a competition such as Poetry Out Loud is that the participants learn public－speaking skills that can help them for life.

    Nowadays six Amazon Scout delivery robots rolled out in a pilot program in Snohomish County, Wash. The robots carry meals, groceries and packages to homes and offices in this region just north of Seattle. They have appeared on the sidewalks of London, Beijing and other cities and communities worldwide. These machines must overcome pedestrian legs, naughty dogs and broken pavement, which raises some questions.

    These services are gaining attraction as a growing number of city residents expect immediate or scheduled delivery for just about everything. Between 2017 and 2018 online retail sales in the U.S. increased by 16 percent. On the final step of all these deliveries, called the last mile, humans on bicycles, motorized scooters (电动车) or large delivery trucks typically deliver packages. All the vehicles compete for space on busy urban streets. "Deliveries are trending upwards in all crowded city centers, and if city and state leaders don't start thinking about creative solutions like robot deliveries, we can expect even worse traffic jams," says Paul Mackie, director of a transportation policy research center in Arlington.

    A study by this center found 73 percent of delivery vehicles in Arlington were parked outside of authorized areas, often blocking bike lanes and crosswalks. By moving the last step of deliveries from the road to the sidewalk, cities could reduce traffic jams and solve the parking problem entirely, Mackie says.

    Companies such as Amazon are not developing this delivery technology simply to clear up urban traffic. Self-driving vehicles and sidewalk robots could cut down last-mile delivery costs in cities by as much as 40 percent, according to a 2018 report by a consultancy firm. A delivery robot can cost thousands of dollars to manufacture, and most currently require human management and conservation. But in the long run companies that use autonomous delivery vehicles in the next several years could end up saving billions of dollars, the report stated.

    We can make mistakes at any age. Some mistakes we make are about money. But most mistakes are about people. "Did Jerry really care when I broke up with Helen?" "When I got that great job, did Jim, as a friend, really feel good about it?" "And was Paul friendly just because I had a car?" When we look back, doubts like these can make us feel bad. But when we look back, it's too late.

    Why do we go wrong about our friends or our enemies? Sometimes what people say hides their real meaning. And if we don't really listen we miss the feeling behind the words. Suppose someone tells you, "You're a lucky dog." That's being friendly. But "lucky dog"? There's a bit of envy in those words. Maybe he doesn't see it himself. But bringing in the "dog" bit puts you down a little. What he may be saying is that he doesn't think you deserve your luck.

    "Just think of all the things you have to be thankful for" is another noise that says one thing and means another. It could mean that the speaker is trying to get you to see your problem as part of your life as a whole. But is he? Wrapped up in this phrase is the thought that your problem isn't important. It's telling you to think of all the starving people in the world when you haven't got a date for Saturday night.

    How can you tell the real meaning behind someone's words? One way is to take a good look at the person talking. Do his words fit the way he looks? Does what he says agree with the tone of voice? His posture(姿态)? The look in his eyes? Stop and think. The minute you spend thinking about the real meaning of what people say to you may save another mistake.

    I was in Walt Disney World with my son, Daniel, who is autistic (患自闭症的), and at that time he was 7 years old. My wife and our three other sons were with us too. He was having one of his melt down screaming tantrums (发怒), only God knows why. So my wife and I decided I would take the bus back to the hotel, and she would stay in the park with the other three children.

After we got on the bus, the screaming continued. My son looks "normal". To the many people on the bus, he appeared to just be a kid screaming — or a spoiled child who did not get his special toy that day. It did not take long — less than a minute — before the screaming brought about stares, then glares from the other passengers.

    To my shame, I found myself losing my temper at my own son. I was embarrassed, angry, and frustrated, and felt cheated by God for not being able to enjoy a normal vacation with my family because of him. I started to wonder what life would be like without having to deal with this cross (痛苦).

    And just as the reactions of the other passengers were becoming most intense, a man seated just in front of me turned around to face me. I cheered myself up for his advice on how to raise a well-behaved child.

    He said calmly, "Is he alright?" I said, "He's autistic." Then the man said, "It's alright." And he smiled. That's all.

    And suddenly, all the anger building up inside me was gone. I almost wept for shame at how I had felt a moment before. It no longer mattered what the other people thought. My son was my gift from God.

    I will never forget that man, nor his small, simple act of kindness and understanding. I truly believe he was my son's guardian angel that day maybe mine too.

Rachel Carson was a science writer widely respected for her books about oceans.But she also devoted years to gathering scientific research that would awaken the public to the dangers of modern chemical pesticides.Her work,Silent Spring,became one of the most influential books of the 20th century.And it launched the modern environmental movement.

Born in Pennsylvania,she became a marine scientist working for the US government,primarily as a writer and editor.Her first three books,Under the Sea-Wind,The Sea Around Us,and The Edge of the Sea were physical explanation of life in and near the sea.They made Carson one of the best-known and respected science writers.But then she turned her time and talents to a new subject.

Carson had been concerned about the dangers of the pesticide DDT since the mid-1940s.At first DDT was a symbol of the progress of modern chemistry.It had saved countless lives by killing lice and mosquitoes that spread deadly diseases.But Carson doubted whether spreading large quantities of poison throughout the environment could be completely safe.She painstakingly gathered research to prove that the chemical industry was overconfident about the safety of chemicals that hadn't been tested.

Carson published her research as a book,Silent Spring,in 1962.It caused an uproar.Carson was immediately attacked by the chemical industry.Millions of citizens tuned in to watch a television program analyzing the issue.Carson's calm and reasoned arguments turned the audience in her favor.Finally,her work convinced the president to call for an investigation.Eventually 12 of the most toxic chemicals Carson wrote about in Silent Spring,including DDT,were banned or cancelled.She grew physically weak and endured a lot of pain.Yet she refused to stop working on the book.She died on April 14,1964,at the age of 56.Her writings helped move the nation toward a new understanding of how humankind depends on the interconnection of all forms of life on Earth.