材科一：

  材料二：2015年1月1日，“史上最严”的新《环境保护》正式实施。环保法的执行不是“棉花棒”，而是“杀手锏”。既要让那些偷偷排放的企业承受付不起的代价，也要对工作不到位、工作不力的执法部门问责．网民纷纷跟贴点赞，从篮篮的天”说重罚治污，蓝天白云指日可待。”

  结合材料，运用所学知识回答．

根据短文理解，从A、B、C三个选项中选择最佳答案填空。

    A young father was visiting an old man. They were standing in the old man's garden and  1  children. The young man said, "How strict should parents be  2their children?" The old man pointed to a line3 a big, strong tree and a thin, 4  one. "Please untie the line," he said. The young man 5 so, and the young tree bent(弯曲) over to one side.

    "Now tie it again," said the old man, "but first pull the line tight(紧紧地) so that the young tree is6  again." The young man did as the old man told him. Then the old man said, "It is the same with  7  . You must be strict with them, but sometimes you must untie the 1ine8 how they are getting on. If they are not yet able to stand alone, you must tie the line tight 9 . But when you find that they are ready to stand alone, you can take the10   away."

生物体越大，构成该生物体的细胞就越大．

在评论商鞅变法时，司马迁说“秦民大悦”，而司马光却说“人多怨之”。史学研究者的正确态度是（  ）