To help the environment, many Americans have made the change from paper and plastic bags to reusable shopping bags.But a report by a Florida newspaper says that reusable shopping bags sold by some supermarkets have high levels of lead(铅), which can be dangerous to humans, especially young children.Now, there's a call for a rethink about the use of reusable shopping bags.

     “When our families go to the store looking for safe and healthy foods, the last thing they should be worrying about is a bag，”Charles Schumer, a government official said.“Quick and complete research will allow everyone to make right decisions.”

    The newspaper bought more than a dozen bags sold at Publix supermarkets from Florida supermarkets to test them for lead.The results showed that certain bags had lead levels that worried health officials.Some bags had enough lead in them to be considered dangerous waste if people were to throw the bags out with other rubbish.Lead in the bags is not likely to move onto food.But over time, paint (油漆) on the bags can break off and the bags can wear out.When this happens, lead can be freed.

    The affected (受影响的) bags were found in Florida.But Publix has more than 1，000 stores across America.Publix says that its bags don't break any laws about lead levels, but that they have asked the makers of the bags to reduce(降低) the lead levels in them.

    The bags with the highest levels of lead had beautiful designs and many pictures.Plain reusable bags without them are found to have little lead.People worried about lead levels in reusable bags can turn to cloth.Paper bags are also a good choice, since paper can be reused.

    Settled by the Celts, invaded by the Romans and the Normans, and ruled by the English, Wales' population has regularly changed over the ages. Wales, particularly South Wales, became a melting pot (熔炉) of European nationalities and cultures. At first workers from England, Ireland and the rural areas of Wales rushed into the coal mines of South Wales. By 1911, workers from Ireland, Italy and Spain had joined the industrial workforce (劳动大军) there. Many of these newcomers were prepared to work for less pay.

    But during this period, workers, dissatisfied with regular pay cuts, poor safety, returned to the land. In 1891, the rural population of Wales was about 616,000 and by 1911 just over 649,000 people lived and worked in these areas.

       The rural population continues to grow slowly even today. People from richer parts of the UK, particularly southern England, are buying holiday homes in Wales. In some areas this has led to a lack of housing for local people. This, combined with the lack of employment in rural Welsh communities, has started a new movement of people in search of jobs and homes into the towns and cities of Wales and to other parts of the UK and Europe.

    As so many Welsh people have moved to other countries over the last 200 years, it's really no surprise that many visitors come to see friends and relatives. These visitors strengthen their links to their land of origin and continue to support the Welsh's development. During the hot summer days, about 28% of the visitors visit the countryside and nearly 70% visit the seaside.

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UC Berkeley

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    Sports shoes that work out whether their owner has done enough exercise to warrant(保证；授权)time in front of the television have been invented in the UK.

    The shoes — named Square Eyes — contain an electronic pressure sensor and a tiny computer chip to record how many steps the wearer has taken in a day. A wireless transmitter(传话器) passes the information to a receiver connected to a television, and this decides how much evening viewing time the wearer deserves, based on the day's efforts.

    The design was inspired by a desire to fight against the rapidly ballooning waistlines among British teenagers, says Gillian Swan, who developed Square Eyes as a final year design project at Brunel University in London, UK. "We looked at current issues and childhood overweight really stood out," she says. "And I wanted to deal with that with my design."

    Once a child has used up their daily allowance gained through exercise, the television automatically switches off. And further time in front of the TV can only be earned through more steps.

    Swan calculated how exercise should translate to television time using the recommended daily amounts of both. Health experts suggest that a child take 12,000 steps each day and watch no more than two hours of television. So, every 100 steps recorded by the Square Eyes shoes equals exactly one minute of TV time.

    Existing pedometers(计步器) normally clip(夹在) onto a belt or slip into a pocket and keep count of steps by measuring sudden movement. Swan says these can be easily tricked into recording steps through shaking. But her shoe has been built to be harder for lazy teenagers to cheat. "It is possible, but it would be a lot of effort," she says. "That was one of my main design considerations."

    March 21 has been declared World Sleep Day, a time to recognize and celebrate the value of sleep. Many sleep experts hope it will be a wake-up call.

    According to a poll (民意调查) by the National Sleep Foundation, nearly 4 in 5 Americans don't get as much sleep as they should during the workweek. On average, adults are thought to need at least eight hours of sleep a night, although some can manage with less and some won't do well without more. But the survey found that, on weekdays, only 21% of Americans actually get a full eight hours of sleep, and another 21% get less than six hours.

    To many of us, the thought of spending more time sleeping is, well, a big yawn. On the other hand, the thought of being smarter, thinner, healthier and more cheerful has a certain appeal. And those are just a few of the advantages that can be ours if we consistently get enough sleep, researchers say. Also on the plus side: We're likely to have better skin, better memories, better judgment, and, oh, yes, longer lives.

    “When you lose even one hour of sleep for any reason, it influences your performance the next day,” says Dr. Alon Avidan, director of the UCLA Sleep Disorders Center.

    A study published last year found the same to be true even of children. When kids aged 8 to 12 slept for just one hour less for four nights, they didn't function as well during the day.

    But sleeping has an image problem.“We see napping or sleeping as lazy,” says Jennifer Vriend, a clinical psychologist in Ottawa, Canada, and the leading author of the study with children.“We put so much emphasis on diet, nutrition and exercise. Sleep is in the back seat. In fact,”she adds,“no matter how much we work out, no matter how well we eat, we can't be in top physical shape unless we also get plenty of sleep.”

    An 80-year-old man was sitting on the sofa in his house along with his 45-year-old highly educated son.

    Suddenly a crow (乌鸦) perched on the tree near their window.

    The father asked his son, "What is this?"

    The son replied, "It is a crow."

    After a few minutes, the father asked his son the second time, "What is this?"

    The son said, "Father, I have just now told you. It is a crow!"

    After a little while, the old father again asked his son the third time, "What is this?"

    "It's a crow, a crow, a crow!" said the son loudly.

    A little after, the father again asked his son the fourth time, "What is this?" This time the son shouted at his father, "Why do you keep asking me the same question again and again? 'IT IS A CROW'. Are you not able to understand this?"

    A little later the father went to his room and came back with an old diary, which he had kept since his son was born. On opening a page, he asked his son to read that page. When the son read it, the following words were written in the diary:

    "Today my little son aged three was sitting with me on the sofa, when a crow was sitting on the window. My son asked me 23 times what it was, and I replied to him all 23 times that it was crow. I hugged him lovingly each time he asked me the same question again and again for 23 times. I did not at all feel annoyed; I rather felt affection for my innocent child."