题干

FeCl3溶液和Fe(OH)3胶体具有的共同性质是

A:滴人盐酸,先产生沉淀,然后沉淀又溶解

B:都能透过半透膜

C:都有丁达尔现象

D:加热蒸干灼烧,最终都有Fe2O3生成

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答案(点此获取答案解析)

D

同类题1

阅读下面文章,完成后面的题。
                                                                                                        鸟坛大嘴大
                                                                                                             瘦驼
        随着《里约大冒险》在全球银幕热播,作为重要配角的热心的拉菲尔也好好地秀了一把。
        巨嘴鸟的大名是鵎鵼,生活在南美洲。全世界现存的34种巨嘴鸟,绝大多数只生活在巴西。
        因为大嘴的眼球效果,巨嘴鸟是最不容易被人认错的鸟。它们的嘴实在是太大了,长度几乎占了身长的三分之一。不过,你不用担心这给巨嘴鸟带来沉重的负担,它的喙里面是泡沫状的,非常轻,重量一般不会超过50克。
        巨嘴鸟为什么会长这么大的嘴?这个问题困扰了科学家很多年。起先,只看到标本的鸟类学家们曾认为,巨嘴鸟的大嘴是用来捉鱼的,就像鹈鹕那样。后来,鸟类学家发现巨嘴鸟的主要食物是各种果子,于是又猜测,或许拥有一张大嘴比较方便啄食长在树梢的果子?直到最近,科学家们才揭开了巨嘴的秘密:原来它们生活在热带雨林,在高温炎热环境下,大嘴可帮助它们散热降温。
        吸引人们注意力的,还有巨嘴鸟的脚。巨嘴鸟有四根脚趾,两根朝前,两根朝后。这种脚型,啄木鸟也有。实际上,巨嘴鸟就是啄木鸟的亲戚,它们与啄木鸟一样,也喜欢住在树洞里。不过,它们并不自己凿洞,一些大型的巨嘴鸟喜欢住在树木腐烂形成的天然树洞里,而一些小型的巨嘴鸟则不客气地借住到亲戚家里,去抢占啄木鸟辛苦开凿的洞穴。
         巨嘴鸟是鸟类中的模范夫妻,大部分巨嘴鸟夫妻会相互厮守很多年。繁殖的时候,巨嘴鸟夫人会产下1~5枚白色的卵,大约经过16天的轮番孵化,小巨嘴鸟就会破壳而出。刚出壳的雏鸟非常虚弱,全身连一根绒毛都没有,双眼紧闭。这个时候,雏鸟的嘴还很短,完全看不出以后会变成一个大嘴巴。巨嘴鸟夫妇会喂刚孵出来的雏鸟吃小虫子,后来,水果逐渐成为小巨嘴鸟的主食。与其他的鸟相比,小巨嘴鸟长得非常慢,有的种类过了满月时身上还没有几根羽毛。
        科学家们最近还发现,有的巨嘴鸟会齐心协力一起抚养雏鸟,即便这些雏鸟并不是它们的孩子。科学家们估计,这些自愿出力的巨嘴鸟“保姆”可能是雏鸟的哥哥姐姐,也就是巨嘴鸟夫妇上一次繁殖的后代。
        经过两个月的悉心哺育,小家伙们终于可以离开巢穴了。这时候,它们除了嘴不够大、颜色不够鲜艳外,基本上跟爸爸妈妈一般模样。至于那张标志性的大嘴,至少需要一年才会完全长成。离巢的幼鸟会跟爸爸妈妈共同生活一段时间。这些小家伙们玩心很重:它们会把大嘴扣在一起互相推挤,谁先后退谁就输了,赢了的一方会再接受其他幼鸟的挑战。它们钟爱的另一种游戏是抛果子。这些游戏,对小巨嘴鸟来说不只是为了玩乐,更重要的是能从中习得生存的本领。那些从小就打遍天下无敌手的小鸟,长大后更可能成为头领。
        目前,大部分种类的巨嘴鸟生活还算无忧无虑,但由于人们大量砍伐森林,导致某些巨嘴鸟的家园遭到破坏,已经有一些陷入濒危状态。就像电影里说的,有些人喜欢把野生的鸟捉来做宠物,这种捕捉甚至形成了交易链(据说,一只巨嘴鸟的身价已经高达10万元),这就严重威胁到了巨嘴鸟的生存。
巨嘴鸟的大嘴闻名天下,绝对是它们种族的“注册商标”。但是,大自然中还是存在着“东施效颦”者,那就是犀鸟。犀鸟生活在亚洲和非洲,它不是巨嘴鸟的近亲,与巨嘴鸟的生活区域也并不重叠,可是,它们也长着一张大嘴!只不过尺码相对巨嘴鸟来说小一些。犀鸟的生活习性与巨嘴鸟很相近,也以水果为主食,偶尔吃些小昆虫、小动物做配菜。这种没有亲缘关系却长得类似的现象,科学家称之为“趋同进化”,也就是本来长得不像,由于生活环境近似,慢慢变成了一个模样。
        我们该如何区分巨嘴鸟和犀鸟呢?第一方法当然是看“出生证”,巨嘴鸟只生活在南美洲,而犀鸟只生活在亚洲和非洲;其次,请它们把脚伸出来,两根脚趾朝前、两根朝后的是巨嘴鸟,三根朝前、一根朝后的是犀鸟;最后一条是看“帽子”,犀鸟的头顶往往“戴”有一个“大头盔”,而巨嘴鸟没有。
                                                                                                (选自科学松鼠会网站 有删改)

同类题4

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    Hilversum is a medium-sized city between the major cities of Amsterdam and Utrecht in the Gooi area of North Holland, the Netherlands. Unlike most of the Netherlands, Hilversum is actually in a hilly area with the soil mostly consisting of sand. Once called the Garden of Amsterdam, it still attracts travelers to come over to cycle and walk through the surrounding forests. They visit it for a relaxing day off from the urban madness. For Dutch people, Hilversum is all about textile (纺织) and media industries, and modern architecture.

    In history, Hilversum was largely an agricultural area. Daily life was marked by farming, sheep raising and wool production. A railway link to Amsterdam in 1874 attracted rich traders from Amsterdam to Hilversum. They build themselves large villas (别墅) in the wooded surroundings of the town. One of the families moving in was the Brenninkmeijers, currently the wealthiest family of the Netherlands. They moved in after big success in the textile industry and aided a substantial textile industry in Hilversum. But the textile boom lasted only several decades. The last factory closed in the 1960s.

    The change to a media economy started in 1920, when the Nederlandse Seintoestedllen Fabriek (NSF) established a radio factory in Hiversum. Most radio stations called in the large villas in the leafy areas of the town. Television gave another push to the local economy. Hilversum became the media capital of the Netherlands, and Dutch televison stars moved into the leafy neighborhoods surrounding the town.

    In the early 1900s, modern architcts W.M. Dudok and J. Duiker placed hundreds of remarkable buildings in Hilversum. These modern architectural masterpieces (杰作) are so many that Hilversum almost feels like an open air museum. Dudok alone shaped most 20th century Hilversum and approximately 75 buildings in 1928-1931. It has wide international fame and is included in many architecture textbooks. The building has a remarkable shape and looks like a combination of “blocks”. Actually, one may start his journey of modern architecture by walking or biking the W.M. Dudok Architectural Route in Hilversum.