题干

大胆科学的假设与猜想是科学探究的先导和价值所在。在下列假设(猜想)引导下的探究肯定没有意义的是(  )

A:探究SO2与Na2O2反应可能有Na2SO4生成

B:探究Na与水反应可能生成NaOH和H2O2

C:探究浓H2SO4与铜在一定条件下反应产生的黑色物质中可能有CuS

D:探究向滴有酚酞的NaOH溶液中通入Cl2,溶液红色褪去的原因是溶液的酸碱性变化,还是HClO的漂白性

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答案(点此获取答案解析)

B

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    When we think about happiness, we usually think of something surprising and unexpected, a top great delight.

    For a child, happiness has a magic quality. I remember playing police and robbers in the woods, getting a speaking part in the school play. Of course, kids also experience lows, but their delight at tops of pleasure is easily seen, such as winning a race or getting a new bike.

    For teenagers, or people under 20, the idea of happiness changes. Suddenly it's conditional on such things as excitement, love, and popularity. I can still feel the pain of not being invited to a party that almost everyone else was going to. I also recall the great happiness of being invited at another event to dance with a very handsome young man.

    In adulthood the things that bring great joy — birth, love, marriage — also bring responsibility and the risk of loss. Love may not last; loved ones die. For adults, happiness is complex.

    My dictionary explains “happy” as “lucky” or “ fortunate”, but I think a better explanation of happiness is “ the ability to enjoy something”. The more we can enjoy what we have, the happier we are. It's easy for us not to notice the pleasure we get from loving and being loved, the company of friends, the freedom to love where we please, and even good health. Nowadays, with so many choices and much pleasure, we have turned happiness into one more thing we have. We think we own the right to have it, which makes us extremely unhappy. So we try hard to get it and consider it to be the same as wealth and success, without noticing that the people who have those things aren't necessarily happier.

    While happiness may be more complex for us, the answer is the same as ever. Happiness isn't about what happens to us. It's the ability to find a positive for every negative, and view a difficulty as a challenge. Don't be sad for what we don't have, but enjoy what we do possess.