属于后天学习行为的是（   ）

中共十八届五中全会公报中提出：坚持计划生育的基本国策，完善人口发展战略，全面实施一对夫妇生育两个孩子政策，积极开展就对人口老龄化行动。中国社科院人口与劳动经济研究所所长张车伟认为，在我国面临人口老龄化加剧和劳动力减少的背景下，这一政策积极调整既顺应了群众对生育二孩的普遍需求.也有助于优化人口结构。这说明（      ）

①联系是普遍的，任意事物之间都是相互联系的

②联系是客观的，但人们可以根据自身需要创造联系

③要着眼于事物的整体性，注意内部结构的优化趋向

④联系是多样的，要一切以时间、地点、条件为转移

②C（s）+O₂（g）═CO₂（g）；△H=﹣393.51kJ•mol^﹣1

则反应C（s）+CO₂（g）═2CO（g）的△H为（   ）

    Long long ago, there was a man living in a village with his wife and two children. They had a hen. It laid a golden egg every day. The man sold the golden egg and the family lived a rich and comfortable life.

    But the man was very greedy (贪婪的). He wanted to get all the golden eggs from his hen at a time. So, he thought hard every day about how to achieve it and he got a plan at last. He decided to kill the hen and get all the eggs. He didn't want to tell his wife about the plan because he wanted to give her a big surprise. He was so excited about his great plan. He even started to sing when he thought of the plan.

    The next day when the hen laid a golden egg, the man couldn't wait to take a knife and cut its body open. However, there was nothing but blood(血液) all around. There weren't any eggs at all. He was very sad because he would not get even one egg now.

    Their life used to be comfortable with one egg a day, but now their life changed a lot.

    How silly he was!