在同一时刻，Windows XP中的“活动窗口”可以有（）。 A.前台窗口和后台窗口

一台理想变压器，原线圈与副线圈的匝数分别为1 100和180，现将变压器原线圈接在交流电源上，设输入电压为U₁，输出电压为U₂，那么    [ ]

A．若U₁=220 V，则U₂=36 V    

B．若U₁=220 V，则U₂=16 V    

C．若U₁=110 V，则U₂=36 V    

D．若U₁=110 V，则U₂=18 V

2010年12月4日是我国第九个“全国法制宣传日”。为了培养同学们法制观念，某校举办了手抄报比赛。九年级二班的同学设计了“以案说法”“法治力量”2个栏目。  2009年12月4日，新疆维吾尔自治区乌鲁木齐市中级人民法院公开开庭审理了打砸抢烧严重暴力犯罪5起案件7名被告人，并当庭作出一审判决。海日妮萨·萨伍提、如则喀日·尼亚孜、李龙飞等4名罪行极其严重的被告人依法被判处死刑，另有1名被告人被判处无期徒刑，3名被告人被判处有期徒刑。

上述材料表明了什么？这样做有什么重要意义？

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Lichens may grow on the bark of a tree in a steaming tropical rain forest, on the bricks of big city buildings, on rocks in hot springs, on wind-swept mountaintops, and in the driest desserts. In the arctic, they provide the principal food for caribou, and they are one of the few plants that grow in Antarctica. They are pioneers, appearing in barren rocky areas and starting the formation of soil in which mosses, then ferns, and then other plants can take root.
Lichens are a partnership of two plants — fungi and algae. The lichen body is made up of a network of fungal strands. In the upper layers of these grow groups of algae. The two organisms live together to the benefit of both, a relationship known as symbiosis. The fungi provide support, absorb water, and shelter the tender algae from direct sunlight. The algae carry on photosynthesis and provide the fungi with food. The algae can live independently and are recognizable as a species that grows alone. The fungi, on the other hand, cannot live apart from their partners. They can be placed in known classes of fungi but are unlike any species that lives independently.
So definite are the form, color, and characteristics of these double organisms that for hundreds of years, they were classified as one. More than 15,000 "species" were named. If these organisms are classified as separate species, it is difficult to fit them into the existing system of classification. But if they are classified separately, these species of fungi seem rather strange. Lichens are a splendid example of the difficulties faced by taxonomists in classifying species.

Which of the following best expresses the main idea of Paragraph 2

A．Because of their characteristics as double organisms, it is difficult to classify lichens.
B．Over 15,000 varieties of lichens have been identified.
C．Double organisms should always be classified as separate species.
D．Taxonomists always find it difficult to classify new species of plants.

在宁德地委强力推动下，赤溪村打响了以转变观念为突破口的“横血”破坚战——“挪穷窝”：用移民搬迁的方式把分散的14个自然村集中起来：通路、通电。搬迁成功了，生活环境改善了，新问题又来了：搬了穷富。靠着人均不足1亩的土地，如何维持穷根，走一条自我致富之路？赤溪村两委干部再次帮助群众转变观念，因地制宜培育旅游特色优势产业。今天，生态旅游已成为赤溪人致富的主导产业，2015年全村人均统统入达1.3万多元，其中45%以上来自旅游业。三十多年来，赤溪村干部群众在党的扶贫政策支持下，在社会各方的大力帮助下，从“输血”帮扶到“换血”搬迁再到“造血”开发，走出了一条适合自身特色的扶富乱贫之路，把一个远近闻名的贫困村建成了小康村。2016年2月19日，习 * * * * 问赤溪村干部群众进行在线支流时指出：“„中国扶贫第一村‟这个评价是很高的，滴水穿石、久久为功、弱鸟先飞，你们的实践印证了现在的扶贫方针，就是要精准扶贫。”赤溪村矢志不渝推进扶贫开发、脱贫致富的艰辛历程，正是中国特色扶贫开发探索之路的一个缩影。改革开放以来，我们党成功走出了一条中国特色扶贫开发道路。使七亿多农村贫困人口成功脱贫，为全面建成小康社会打下了坚实基础。当前，我国脱贫攻坚已进入冲刺阶段。习 * * * * 指出：“全面建成小康社会，关键是要把经济社会发展的„短板‟尽快补齐”，而“农村贫困人口脱贫是最突出的短板”，“脱贫攻坚战的充锋号已经吹响，我们要立下愚公移山志，咬定目标、苦干实干，坚决打赢脱贫坚战。”摘编自人民网（2016年2月1日、11月9日）、新华网（2016年7月25日）、央视网（2016年8月6日）等

东溪村脱贫致富之路对我国实施精准扶贫、打赢脱贫攻坚战有何启示？

地面各测点的粉尘浓度规定每月测定（）。

A、1次

B、2次

C、3次

D、4次