2014年3月20日，中国******在访问德国时指出，中国绝不走“国强必霸”的道路，但中国也再不能重复鸦片战争以后在列强坚船利炮下被奴役被殖民的历史悲剧。材料表明（  ）

①中国坚定地维护自己的国家利益

②中国始终不渝地走和平发展道路

③世界多极化趋势在曲折中发展

④维护国家安全是我国外交政策的宗旨

    Ben and Jim are twin brothers. They are nine. They are pupils. They study in Yuxin Primary School. They are in the same class. Everyday they go to school and come back together.

    Their teacher, Mrs. Green, says to the pupils. Please write a composition (作文) 'My Mother'.

    Jim is a good boy. He writes the composition at home. But Ben plays football with his friends. The next day Mrs Green says to the class, “I read your compositions today. But two of yours are just the same.” Ben stands up and says, “Jim and I are twins. We have the same mother.”

材料一：“外争国权、内惩国贼”、“拒绝在和约上签字”、“废除二十一条”。

材料二：“中国的土地不可征服，也不可断送！中国的人民可以杀戮，而不可以低头!”

材料三：“6月5日上海日商纱厂的中国工人首先罢工……接着机器、纺纱、印刷、公共交通、码头、船坞等行业的工人相继罢工。”

若a满足不等式组$\left\{\begin{array}{c}2a-1\le 1\\ \frac{1-a}{2}>2\end{array}\right.$，则关于x的方程（a﹣2）x²﹣（2a﹣1）x+a+$\frac{1}{2}$=0的根的情况是（　　）