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    符彦．卿字冠侯，陈州宛丘人。彦卿年十三，能骑射。事庄宗于太原，以谨愿称，出入卧内，及长，以为亲从指挥使。入汴，迁散员指挥使。郭从谦之乱，庄宗左右皆引去，惟彦卿力战，射杀十数人，俄矢集乘舆，遂恸哭而去。天成三年，以龙武都虞候、吉州刺史讨王都于定，大破契丹于嘉山。尝射猎遂城盐台淀，一日射獐、彘、狼、狐、兔四中二，观者神之。晋天福初，授同州节度．。兄彦饶亦镇滑台。俄而彦饶叛，彦卿上表待罪，乞田里，晋祖释不问。改左羽林统军，俄兼领右羽林，改镇部延。辽人南侵，诏彦卿率所部拒战澶洲。契丹骑兵数万围高行周于铁丘。诸将莫敢当其锋，彦卿独引数百骑击之，辽人遁去，行周得免。又副李守贞讨平青州杨光远，移镇许州，封祁国公。开运二年，与杜重成、李守贞经略北鄙。契丹主率众十余万围晋于阳城，军中之水，凿井辄坏，争绞泥吮之，人马多渴死，时晋师居下风，将战，弓弩莫施。彦卿谓张彦泽、皇甫遇曰：“与其束手就擒，曷若死战，然未必死。”彦泽等然之。遂潜兵尾其后顺风击之契丹大败其主乘橐驼以遁获其器甲旗仗数万以归少帝嘉之改武宁军节度同平章事。彦卿将家子，勇略有谋。存审之第四子，军中谓之“符第四”。前后赏赐钜万，悉分给帐下，故士卒乐为效死。辽人自阳城之败，尤畏彦卿，或马病不饮乾，必唾而咒曰：“此中岂有符王邪了”晋 少主既陷契丹，德光之母问左右曰：“彦卿安在？或对曰：“闻其已遣归徐州矣。”德光母曰：“留此人中原，何失策之甚！”其威名如此。

2016年7月，特蕾莎·梅正式接任英国首相，成为英国历史上第二位女首相。她在上任后的首次演讲中讲到：“我刚去过白金汉宫，女王陛下要我组建新政府，我接受了。”“卡梅伦领导了一个统一的政府，我也将本着这种精神执政。不是所有人都清楚，我所在的党的全称是保守和统一党，其中的“统—”一词对我而言至关重要。”“我领导的政府不会被小撮特权群体的利益驱使，而会因你的利益而奔走。”“我们要让英国成为一个为每个人服务的国家，而不只是为少数特权阶层服务的国家。“

运用《国家和国际组织常识》的知识，结合材料，回答下列问题：

已知函数 $f\left(x\right)=2\text{ln}x+x^3-ax$ .

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    Some people will do just about anything to save money．And I am one of them．Take my family's last vacation．It was my six­year­old son's winter break from school, and we were heading home from Fort Lauderdale after a week long trip．The flight was overbooked, and Delta, the airline, offered us $400 per person in credits to give up our seats and leave the next day．I had meetings in New York, so I had to get back．But that didn't mean my husband and my son couldn't stay．I took my nine­month­old and took off for home．

    The next day, my husband and son were offered more credits to take an even later flight．Yes, I encouraged — okay, ordered — them to wait it out at the airport, to “earn” more Delta Dollars．Our total take: $1,600．Not bad, huh?

    Now some people may think I'm a bad mother and not such a great wife either．But as a big­time bargain hunter, I know the value of a dollar．And these days, a good deal is something few of us can afford to pass up．

    I've made a living looking for the best deals and exposing（揭露）the worst tricks．I have been the consumer reporter of NBC's Today show for over a decade．I have written a couple of books including one titled Tricks of the Trade: A Consumer Survival Guide．And I really do what I believe in．

    I tell you this because there is no shame in getting your money's worth．I'm also tightfisted when it comes to shoes, clothes for my children, and expensive restaurants．But I wouldn't hesitate to spend on a good haircut．It keeps its shape longer, and it's the first thing people notice．And I will also spend on a classic piece of furniture．Quality lasts．

广西壮族自治区成立50年来，始终把发展作为解决民族问题的根本途径。这是因为各民族共同繁荣( )