黑土地、黄土地指的是东北平原和长江中下游平原。

如图，已知OPQ是半径为1，圆心角为 $\frac{\pi }{3}$ 的扇形，C是扇形弧上的动点，ABCD是扇形的内接矩形．记∠COP=α，则矩形ABCD的面积最大是____．

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    Interested in getting ahead over the summer? Then stay on course by taking advantage of Alvernia's Summer Session. It lets you get ahead with a large selection of undergraduate and graduate courses. You can attend the class in classrooms or online, or you can take blended (混合的) courses if you like. We offer several flexible sessions at all three locations in the summer to help move you closer toward graduation. All courses are officially recognized and credits you earn are transferable (可转移的).
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下列做法体现“我国的基本政治制度”这一主题的是（   ）

①石家庄市人大常委会批准《2015年市本级预算调整方案（草案）》         

②石家庄市某社区居委会向居民会议汇报工作，接受监督和质询

③中共中央召开党外人士座谈会，征求对经济工作的意见和建议

④新疆维吾尔自治区高级人民法院依法行使自治权，审判爆恐分子

如图，在边长为e（e为自然对数的底数）的正方形中随机撒一粒黄豆，则它落到阴影部分的概率为____