填反义词。

旧——____    无——____    南——____    寒冷——____    矮——____

如图是研究物体的重力势能与哪些因素有关的实验．图中三个相同的木桩被从空中静止释放的铁块A、B、C撞击后陷入沙坑的情况，在此实验中，m_A=m_C＜m_B，铁块所处的初始高度h_A=h_B＜h_C．

   Mrs. Thompson came to the 5th grade class and noticed that Teddy was always alone. Also, he did badly in his studies. When she reviewed Teddy’s past records，she find he was a good child at first，but he began to change when his mother got ill. Finally he lost interest in school after his mother’s death.
   Mrs.Thompson realized the problem and felt sorry for him. She felt even worse when her students brought her beautifully-covered Christmas presents. His presents were covered with some old paper. Some children laughed when she found a bracelet(手镯)with some of the stones missing, and a bottle with a little perfume(香水). But she said how pretty the bracelet was, putting it on, and dabbing some perfume on her hand. Teddy stayed after school for a long time just to say，“Mrs.Thompson，today you smelled just like my mom used to.” After the child left，she cried for quite a long time.
   On that very day，she taught not only knowledge but also children. As she worked with Teddy，his mind seemed to come alive. By the end of the year，Teddy had become one of the smartest children in the class.
   A year later，Teddy left school. She found a note under her door，from Teddy，saying that she was the best teacher he ever had in his life. After that, these words were repeated in each of his letters to her.
   Then after he finished college, Teddy wrote telling her that he had met a pretty girl and was going to get married. He explained that his father was dead，and that he wondered if Mrs.Thompson might sit at the wedding in the place for the mother of the groom(新郎).
Of course，Mrs.Thompson did. She wore the bracelet and the perfume that Teddy remembered his mother wearing on their last Christmas together.
   They hugged(拥抱)each other，and Teddy whispered in Mrs.Thompson's ear，“Thank you，Mrs.Thompson，for making me feel important，and showing me that I could make a difference. ”
   Mrs.Thompson，with tears in her eyes，whispered back，“Teddy，it's not like that. You were the one who taught me that I could make a difference. I didn’t know how to teach until I met you.”

比的前项=____×比值

比的后项=____．

人口迁移率是指一定时期，某地区人口迁入、迁出的绝对量与该时期该地区总人口数之比。人口迁移率－迁入率=迁出率。读我国东南沿海某地区建国以来人口迁移率随时间变化示意图，完成下面小题。