将一根3.5米长的竹竿插入游泳池池底，露出水面的部分长1.9米，这儿的水深多少米？

初二(7)班举行班长竞选，小华同学以全票当选。对此班级同学谈了自己的看法：小华把班级的事情当成自己的事情，小华同学成绩优秀，经常把一些好的学习方法毫无保留的告诉别人，为班级做出了贡献。小华说：只有大家共同努力，才能共同进步，创建优秀班集体。这说明(   )
①集体的发展离不开每个成员的努力②没有个人的努力，就没有集体的发展③只有全班同学团结一致，共同努力才能创建优秀班集体④集体的发展需要发扬团结的精神

根据短文理解，从给出的A、B、C三个选项中选择最佳答案填空。

    All parents love their children. Many parents want their kids to1 well-known people when they2 . Most of them want their kids to live better than others. Many of them 3their kids will be singers or actors. Actors and singers can 4 money easily in our country. When they appear in the advertisement, they will get 5 money which a farmer or a worker can't make all his life. Some of the parents want their kids to be businessmen6doctors. If they work hard, they will have cars and big houses in several 7. Some parents want their kids to work in cities and towns. They don't 8 them to work in the countryside. People who work in the cities and towns can get money after they 9. If you are a famous man, especially an actor, you'll get much but pay a little. A farmer is 10 , he gets little but pays much.

在测量额定电压为“2.5V”小灯泡电功率（正常发光时电阻约为10Ω）的实验中，电源为两节新干电池．

阅读下面的文言文，完成后面问题。
      余忆童稚时，能张目对日，明察秋毫。见藐小微物，必细察其纹理。故时有物外之趣。
      夏蚊成蕾，私拟作群鹤舞空。心之所向，则或千或百果然鹤也。昂首观之，项为之强。又留蚊于素帐中，徐喷以烟，使其冲烟飞鸣，作青云白鹤观，果如鹤唳云端，怡然称快。
      于土墙凹凸处，花台小草丛杂处，常蹲其身，使与台齐，定目细视。以丛草为林，以虫蚁为兽，以土砾凸者为邱，凹者为壑，神游其中，怡然自得。
一日，见二虫斗草间，观之正浓，忽有庞然大物，拔山倒树而来，盖一癞蛤蟆也。舌一吐而二虫尽为所吞。余年幼，方出神，不觉呀然惊恐；神定，捉蛤蟆，鞭数十，驱之别院。