如图，同样高的旗杆，离路灯越近，它的影子就越____ 

材料一：达尔文在他于1859年出版的主要著作《物种起源》中更详细地阐述了自己的思想。……在浅色的桦树林里，浅色种类的蛾通常是深色种类的蛾的6倍；相反，在深色的松树林里，深色种类的蛾通常为浅色种类蛾的16倍。

——（美）斯塔夫里阿诺斯《全球通史》

材料二：达尔文的进化论第一次对整个生物界的发生、发展，做出了唯物的、规律性的解释，推翻了神创论等唯心主义、形而上学在生物学中的统治地位，使生物学发生了一个革命性变革……它奠定了人类对生物进化认识的基础，随着近代科学的发展，人们必然会更加深入地认识生物进化的规律，更有成效地改造自然。恩格斯认为它是“19世纪自然科学的三大发现之一”。

——《生物进化论的“进化”过程》

材料三：尽管达尔文主义受到宗教界和其他集团的敌视，它还是对西方社会有着深远的影响。……例如，政治上，这是俾斯麦以血和铁统一德国的时期。各国的民族主义赞美者认为达尔文主义给了他们支持和正当理由。……经济生活中，这是自由经营和粗鲁的个人主义的时期。舒适的、心满意足的上、中层阶级激烈反对国家为促进较大的社会平等而作出的任何干预。……19世纪后期也是殖民地扩张的黄金时期……有人争辩说，殖民地是强国的繁荣和生存所必需的；还有人争辩说，按照世间的成就判断，诸土著民族软弱、低劣，需要优越的、较强大的欧洲人的保护和指导。

——（美）斯塔夫里阿诺斯《全球通史》

    “Years ago when I was at the Grand Canyon, I remembered someone coming up to the canyon's edge, taking a shot with a camera and then walking away, like 'got it – done', barely even glancing at the magnificent scene in front of him,” Linda Henkel, a scientist at Fairfield University, US told Live Science.

    Henkel was surprised by how obsessed (痴迷的) people are with taking pictures these days - before dinner, during friends' birthday parties, on museum tours and so on.

    They keep taking pictures because they think that it helps record the moment, but as Henkel's latest study has just found out, this obsession may prevent their brains remembering what actually happened, reported The Guardian.

    In her study, Henkel led a group of college students around a museum and asked them to simply observe 15 objects and photograph 15 others. The next day the students' memory of the tour was tested, and the results showed that they were less accurate in recognizing the objects and they remembered fewer details about them if they photographed them.

    ''When people rely on technology to remember them — counting on the camera to record the event and thus not needing to attend to it fully themselves, it can have a negative impact on how well they remember their experiences,” Henkel explained.

    But there is also an exception: if students zoomed in to photograph part of an object, their memory actually improved, and those who focused the lens (镜头) on a specific area could even recall parts that weren't in the frame.

    So basically, this study is saying that constantly taking pictures can harm your memory. But shouldn't reviewing pictures we have taken help wake up our memories? This is true, but only if we spend enough time doing it.

    “In order to remember, we have to access and interact with the photos, rather than just collect them,” Henkel told The Telegraph. However, previous research has shown that most people never take the time to look over their digital pictures simply because there are too many of them and they aren't usually very organized on their computers.

如图，∠AOB=90°，C、D是的三等分点，AB分别交OC、OD于点E、F，求证：AE=CD．

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