题干

为了测定某地石灰石中碳酸钙的质量分数,某同学取样品12 g放入烧杯中,加入稀盐酸至恰好不再产生气体时消耗稀盐酸l00g(石灰石中的杂质均不溶于水且不与盐酸反应),反应后测得烧杯中剩余物质的总质量为107.6 g。
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    Today, we are told, children don't spend enough time in the fresh air. Many of them are addicted to screen on a computer or a TV—they seem to be living in a virtual world. They have lost touch with nature.

    But now 400 organizations in the UK, from playgroups to the National Health Service, are encouraging children to have some “wild time”. They want kids to swap at least 30 minutes of watching TV or playing computer games for time playing outside. Activities such as building dens, climbing trees, rummaging for conkers and playing hide and seek are just some of the things kids can do. Even if they live in a city, they can go on adventures in the garden or the park.

    Children often need a helping hand from mom and dad. They need to be shown what to do and where to go. Andy Simpson from National Health Service says, “We want parents to see what this magical wonder product does for their kids' development, independence and creativity, by giving wild time a go”.

    So despite the complicated world that young people grow up in now, it seems that going back to basics and experiencing “nature's playground” is what modern children need. David Bond from Project Wild Thing says, “We need to make more space for wild time in children's daily routine, freeing this generation of kids to have the sort of experiences that many of us took for granted”.

    This might sound a bit old fashioned to you or maybe, like me, it's made you think about sticking on your boots, getting outdoors and reliving your childhood. There is no age limit on enjoying yourself!