如果一个单项式﹣ $\frac{a^{2}b}{2}$ 的系数和次数分别为m，n，那么 $\frac{mn}{3}$ =____．

根据短文内容和所给中文提示，写出空白处各单词的正确形式。每空限填一词。
    Season Two of Where Are We going, Dad?, a show on Hunan TV, is even more ____(令人兴奋的) than the first.
    Huang Lei— a director，actor，singer and teacher, is a good father. He couldn't be more ____(耐心的) and had to ____(惩罚) Duoduo, his daughter for making some ____(错误) when he takes care of her. As a smart father, Lu Yi certainly knows how to look ____(有帮助的). His daughter Bei'er is a ____(明智的) child who behaves well. And Yang Wei has showed his quiet side. And Yang's good life ____(技能) make it quite easy for him to look after his son on his own. And Yang Yangyang is a good ____(例子) of the saying, "Like father, like son". Malaysian singer Gary Chaw certainly knows how to get along with his ____(孩子们)，Joe and Grace, the brother and sister are sweet. The family laugh and cry ____(一起) and share their most unforgettable moments with each other.

读下列材料，完成下列问题。

材料一 下图是某地不同时间段城区范围变化及对应的人口密度变化示意图。

材料二 世界37城市人均产值与人均轿车使用量。   材料三 漫画《不堪重负》。

 

将适当的物理名词填在方框中．

①____；

②____．

读图，回答下列问题：