题干

  2015年10月,中共十八届中央委员会第五次全体会议公报指出:促进人口均衡发展,坚持计划生育的基本国策,完善人口发展战略,全面实施一对夫妇可生育两个孩子政策,这是继十八届三中全会决定启动实施“单独二孩”政策之后的又一次人口政策调整。下图为“中国人口增长趋势及预测图”,a、b、c分别代表出生率、死亡率和自然增长率。据此完成下列各题。

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                                                                                         Saying no starts small
   “All right then — just one more piece...” Words every girl has said when they are faced with the delicious cheesecake. Of course, many of us know we may eat the whole thing in the end.
    It isn't just girls. Most of us find it hard to say “no” to something attractive. However, scientists now say that willpower is very important to success and a happy life.
    Scientists in different countries have been studying the effects of willpower on people's lives for a long time. The results are similar, according to an article on February 7 in the Guardian, a famous British newspaper.
    In one experiment, scientists told young children that they could either have a marshmallow (圆形软糖) now, or two marshmallows in 15 minutes. Waiting obviously needed more willpower. Scientists then continued studying the children as they grew up. They wanted to see if some children always had stronger willpower. They also wanted to see how having stronger willpower affected their lives.
    Years later, scientists found that the children who had waited for two marshmallows were all healthier, happier and richer adults. Oppositely, the children who had shown weaker willpower at that young age were more likely to be in low-paid jobs, to be overweight, to have social problems.
    But there is hope, Roy F Baumeister, an American social psychology(心理学) professor (教授) told the Guardian. Baumeister says we can train our willpower just like we train our muscles(肌肉). Even a little practice can strengthen(加强) our overall self-control if we do it regularly.
You could start by making yourself stand up straight, speaking in complete sentences, or using a computer mouse with the other hand. Scientists have found that people who manage to change little habits often perform much better in laboratory willpower tests.
    Like muscles, willpower can “get tired”. Don't try to do too many things at the same time, or when you don't have enough energy, for example when you are ill. If you already feel tired, you can try to recharge(恢复) your willpower with a good night's sleep and by eating well.