人与人的合作不是人力的简单相加。假定每个人的能力都为1，那么10个人的合作结果有时比10大，有时甚至比10还小。一个人敷衍了事，两个人相互推诿，三个人永无宁日，这种教训是十分深刻的。对这一现象认识正确的是（    ）

①如果人们相互推诿责任，结果只能是一事无成

②社会需要相互合作，需要每个人承担一定的责任

③社会分工不同，不同职业的人都应该对自己所从事的职业负责

④由于人的素质不同，人与人之间的合作都是很难成功的

如图所示，某带电粒子在电场中运动，轨迹如图中虚线所示，则可判定

汽水中溶有较多的二氧化碳，称为碳酸饮料。

根据短文理解，完成各题任务。
C
    Sally is an English girl. She is my English teacher, Mrs. Brown's daughter. She is only five years old. (A)She can't go to school. She likes playing ping-pong.
    Her favorite ping-pong player is Zhang Yining. Sally is in the ping-pong club. She goes to the ping-pong club every day. She plays ping-pong for two hours there.
    Sally has a sister. Her name is Maria. She is in our class. She likes running. She runs with her mother every morning. (B)她最喜欢的赛跑明星是刘翔. Maria says she wants to be a running star like Liu Xiang.

电解原理在化学工业中有广泛应用．如图表示一个电解池，装有电解液a；X、Y是两块电极板，通过导线与直流电源相连．请回答以下问题：