Scientists are debating how to limit their newly-discovered power to change genetic structure (结构). Scientists already modify the genes (基因) of farm animals and agricultural plants to make them more productive or stronger. But now they can also change genes in wild animals and plants. These genes would continue into later generations. For example, it may be possible for scientists to remove from existence the kind of mosquitoes, small flying insects, that carry the Zika virus. They might also be able to permanently remove species (物种) of plants and animals that are damaging to other species.

    In a report published last week, the U. S. National Academies of Sciences, Engineering and Medicine (NAS) said it supports continued research on this kind of gene control. But it warned that it is not possible to know what will happen when these changed plants and animals are released (释放) into the wild.

    Sixteen biologists, ethicists (伦理学家) and policymakers are on an NAS committee that is examining the issue. They say that there is value to the new technology. But, they say, there is not enough evidence to support the release of modified organisms (生物体) from the laboratory into nature.

    Many people would support stopping mosquitoes and rats from carrying diseases. But scientists say we must understand the possible scientific, ethical, legal and social results of such action before we decide whether to take it. Gene modification is spread through reproduction (繁殖).

    Changed genes will continue to spread as long as an animal or plant continues to reproduce. They cannot be limited to a farm or kept within a country's borders. Scientists are wondering what may happen if a modified organism mates with another species. They are not yet sure how the modified genes would affect the other species. It is possible that those genes could harm those creatures or even lead to their disappearance from our planet.

    When it's five o'clock, people leave their office. The length of the workday,for many workers,is defined by time. They leave when the clock tells them they're done.

    These days, the time is everywhere: not just on clocks or watches,but on cell-phones and computers.That may be a bad thing,particularly at work.New research shows on that clock-based work schedules hinder morale and creativity.

    Clock-timers organize their day by blocks of minutes and hours.For example: a meeting from 9 a.m. to 10 a.m., research from 10 a.m.to noon,etc.On the other hand,task-timers have a list of things they want to accomplish.They work down the list,each task starts when the previous task is completed.It is said that all of us employ a mix of both these types of planning.

    What,then,are the effects of thinking about time in these different ways? Does one make us more productive? Better at the tasks at hand? Happier? In experiments conducted by Tamar Avnet and Anne-Laure Sellier,they had participints organize different activities-from project planning,holiday shopping,to yoga-by time or to-do list to measure how they performed under "clock time" vs "task time".They found clock timers to be more efficient but less happy because they felt little control over their lives.Task timers are happier and more creative,but less productive. They tend to enjoy the moment when something good is happening,and seize opportunities that come up.

    The researchers argue that task-based organizing tends to be undervalued and under-supported in the business culture.Smart companies,they believe,will try to bake more task-based planning into their strategies.

    This might be a small change to the way we view work and the office,but the researchers argue that it challenges a widespread characteristic of the economy: work organized by clock time.While most people will still probably need,and be,to some extent,clock-timers,task-based timing should be used when performing a job that requires more creativity.It'll make those tasks easier,and the task-doers will be happier.

    Recently, South Korean star PSY's “Gangnam style” video has been popular on the Internet. It has become most people's favorite music.

In fact, the song has set the Guinness World Record for the most popular video in the history of the Internet. More than two million people have said “like” since the song was on the Internet on July 15.

    PSY's special dance moves and funny horse riding style have attracted many people. Although many people do not understand the language, the video has become the talk of the Internet. The song has come to first place in the music charts in 31 countries, including the United States, the United Kingdom, and Canada.

    “I just sang for my South Korean fans. I have never expected it to be popular in other countries,” PSY told the reporters on a concert. The song was so popular that a few of South Korean's politicians showed PSY's moves to attract supporters.

    “The song came out in mid-July. It sings about the rich life of South Korea--especially Gangnam in Seoul, where a lot of rich people live.

    Millions of people have watched the video. Many stars, such as Katy Perry, Robbie Williams and Nelly Furtado said that they love the song. These stars performed part of the song at a recent concert.

    Riding high on the success of “Gangnam Style”, PSY was signed by Scooter Braun to Braun's Schoolboy Records, a label distributed by Universal Republic.

    PSY has written many hit songs of varying styles for different singers. Prior to “Gangnam Style” his most famous composition perhaps was Lee Seung Gi's debut(首次亮相) song “Because You Are My Woman”.

    I don't think there is anything more important than health. “Health is the greatest wealth，” wise people say. You can't be good at your studies or work well when you are ill.

    If you have a headache, toothache, backache, earache or bad pain in the stomach, if you complain of a bad cough, if you run a high temperature and have a bad cold, or if you suffer from high or low blood pressure, I think you should go to the doctor. The doctor will examine your throat, feel your pulse, test your blood pressure, take your temperature, sound your heart and lungs, test your eyes, check your teeth or have your chest X-rayed. After that, he will advise some treatment, or some medicine. The only thing you have to do is to follow his advice.

    Speaking about doctor's advice, I can't help telling you a funny story. An old gentleman came to see the doctor. The man was very ill. He told the doctor about his weakness, memory loss and serious problems with his heart and lungs. The doctor examined him and said there was no medicine for his disease. He told his patient to go to a quiet place for a month and have a good rest. He also advised him to eat a lot of meat, drink two glasses of red wine every day and take long walks. In other words, the doctor advised him to follow the rule: "Eat with pleasure, drink with pleasure and enjoy life as it is." The doctor also said that if the man wanted to be well again, he shouldn't smoke more than one cigarette a day. A month later the gentleman came into the doctor's office. He looked cheerful and happy. He thanked the doctor and said that he had never felt a healthier man." But you know, doctor," he said, “it's not easy to begin smoking at my age.”

    There are 5.25 trillion pieces of plastic trash in the world's oceans, and each year, 8 million tons of plastic are added to the figure. Though the oceans seem vast enough to stomach a lot of plastic, the level of waste is starting to reach a crisis point: According to a new report by the Ocean Conservancy, by 2025, the ocean could contain one ton of plastic for every three tons of finfish.

All these floating bits of plastic not only disrupt marine ecosystems, but they also poison the global supply of seafood. “It's reaching crisis proportions,” says Andreas Merkl, CEO of the Ocean Conservancy. “Plastic breaks down into small pieces that look like plankton and is eaten by everyone from plankton to whales.” Plastic acts as a pollution sponge in the ocean, so when wildlife swallow pieces, the plastic might as well be a poison pill.

    The new report calls for a focus on improving waste management systems in a handful of developing countries that are most responsible for the plastic leakage into the ocean. China, Indonesia, the Philippines, Thailand and Vietnam contribute more than half of the oceans' plastic since their waste facilities hasn't kept up with rapid industrialization.

    On average, only about 40% of waste in these countries is actually picked up for disposal. But it's not just uncollected waste floating around-though that is three-fourths of the problem. The other quarter of the oceans' plastic came from post-collection activities. Even when a waste management company picks up waste to landfill it, poorly equipped landfills or illegal dumping mean that trash still ends up in the ocean.

    But how can countries stop the leakage of waste into the ocean? The Ocean Conservancy report suggests five “levers”: waste collection services, closing the leakage points within the collection system, gasification and burning of waste, and recycling facilities. The average waste ends up as litter. Just by expanding collection systems and plugging up their leakage points, the report says plastics leakage could by cut by 50% by 2020.

    It's not just an environmentalist's daydream. Coca-Cola and Dow Chemical, along with some other multinational companies have joined forces with Ocean Conservancy to fight ocean pollution. “We're committed to working toward a future of a plastic-free ocean. Companies don't make plastic with the intent of it ending up in the ocean, and we acknowledge the strong role industry must play in order to help eliminate ocean plastic waste by 2035.” Says Dow Packaging and Speciality Plastics' global sustainability director in a press release.

    Merkl emphasized that the countries can't recycle their way out of the problem. Only about 20% of the waste is valuable enough to be worth recycling: the rest, needs to be sent to sanitary landfills or waste-to-energy plants. “You have to concentrate on the fundamentals of waste management,” he says. And while building landfills and incinerators(焚化炉)across these developing countries might not be pretty, it's far more environmentally friendly than letting waste slide into the world's oceans.

    Even now, almost a year after their astonishing act of group heroism, the dozens of people who risked their lives to save two boys from drowning in Panama City Beach, are still remembered.

    The story began on July 8, 2017. Members of the Ursrey family, eight in total, were enjoying an evening together at the beach. As the sun sank lower on the horizon（地平线）, the two boys—Noah, 11, and Stephen, 8—took their skateboards and walked into the waves without the grown-ups noticing. When the boys were about 70 yards from shore, they realized that the ocean pulled them out to sea. After trying and failing to paddle（涉水）back, they started waving and screaming for help. But the lifeguards had clocked out for the evening.

    The boys had been struggling for several minutes when Brittany and Tabatha Monroe, a married couple from Georgia, wandered by. They didn't see the boys at first, but they heard them.

    They jumped into the water and easily reached the brothers, who were still in fairly shallow water. The woman reassured the frightened boys and seized their skateboards, telling them they would be safe and then discovered that they, too, were now in a world of trouble. They couldn't get back to shore and could barely and only occasionally hit the sandy bottom with their feet. After a few minutes, it was clear to the woman that they were all trapped in a terrible whirlpool.

    Then scores of tourists were walking to them, hand in hand, forming a line. Soon the first person held the woman's hand. In turn, her husband and the two boys joined her. The long line moved slowly until they were back to the safety of the beach.

    The rescuers call it the Human Chain. But it was the deeply “human” aspect of the rescuers' cooperation（合作）that made it so astonishing and successful.