发展基层民主，是社会主义民主最为广泛而深刻的实践，也是发展社会主义民主的基础性工作。目前，我国基层民主建设的主要内容是
①民自治    ②城市居民自治   ③乡镇政权建设   ④企事业单位工会建设

阅读《今天你“微博”了吗》一文，完成小题目。
        ①微博出现于2006年，自进入大众视野以来，迅速传播。从唐骏和方舟子的学历门之争，到河北的“我爸是李刚”事件，再到上海11·15火灾事故的网上直播，微博在几次事件中均表现其便捷性和实时性的特点，在当今的互联网生活中扮演起越来越重要的角色，现已成为一个分享有用信息和知识的强大平台。
        ②微博的最初用途是让人们每时每刻都能向外界播报自己的所作所为。目前，这还是微博的主要用途。由于微博的使用，人们开始能够创造并传播信息，而不是像以前那样只是消费信息——消费他人传播和“控制”的信息。如此一来，人们获取信息的渠道得以进一步地拓展。
        ③微博的另一种用途是作为一种非正式渠道，对会议进行实时报道。与会者可以把会议内容贴到接收信息来源更新的公共订阅网站，这样就可以使那些没有参加会议的人“听到”发言人正在讲什么内容了。这样做还可以使那些与会人员看到其他人对发言人所讲内容的理解和反馈，并且经常会在此后某个时刻引发对该话题的进一步讨论。这样一来，这个订阅网站就变成了思想和观点的档案库，对与会者来说，它是未来很有价值的参考资料。把微博作为传播会议内容的一种非正式渠道也是一种良好的市场营销演练，因为目标事件会得到相当大的曝光率。
        ④此外，微博还能够使人们参与到具有重要社会和政治意义的问题的讨论中来。微博用户贴出关于危机情境的实时新闻不断更新，几秒钟内全世界的读者都能看到这条新闻，这种现象已是司空见惯。众多的从政人士和政府机构现在都在用微博发布公告。
        ⑤微博这种社交网络已经对社会产生了深远的影响。如今，网络上广为流传的招呼语已然变成了：朋友，今天你“微博”了吗？

已知A，B，C，D四点共面，BC=2，AB²+AC²=20， $\overrightarrow{CD}=3\overrightarrow{CA}$ ，则| $\overrightarrow{BD}$ |的最大值为____．

小明在医院看到一种输液警报器（如图甲），当管内药液流完时，电铃发声，报警器内部有一可变电阻，当输液管内有液体时，电阻大，无液体时，电阻小，电路如图乙所示，则当闭合开关报警器工作时，分析正确的是（　　）

根据短文内容，选择最佳答案。
    “Did you hear what happened to Adam Last Friday?” Lindsey whispers to Tori.
    With her eyes shining, Tori brags, “You bet I did, Sean told me two days ago.”
    Who are Lindsey and Tori talking about? It just happened to be yours truly, Adam Freedman. I can tell you that what they are saying is (a) not nice and (b) not even true. Still, Lindsey and Tori aren't very different from most students here at Linton High School, including me. Many of our conversations are gossip(闲话). I have noticed three effects of gossip: it can hurt people, it can give gossipers a strange kind of satisfaction, and it can cause social pressures in a group.
    An important negative effect of gossip is that it can hurt the person being talked about. Usually, gossip spreads information about a topic-breakups, trouble at home, even dropping out-that a person would rather keep secret. The more embarrassing or shameful the secret is, the juicier the gossip it makes. Probably the worst type of gossip is the absolute lie. People often think of gossipers as harmless, but cruel lies can cause pain.
    If we know that gossip can be harmful, then why do so many of us do it? Theanswer lies in another effect of gossip: the satisfaction it gives us. Sharing the latest rumor(传言) can make a person feel important because he or she knows something that others don't. Similarly, hearing the latest rumor can make a person feel like part of the “in group.” In other words, gossip is satisfying because it gives people a sense of belonging or even superiority(优越感).
    Gossip also can have a third effect: it strengthens unwritten, unspoken rules about how people should act. Professor David Wilson explains that gossip is important in policing behaviors in a group. Translated into high school terms, this means that if everybody you hang around with is laughing at what John wore or what Jane said, then you can bet that wearing or saying something similar will get you the same kind of negative attention. The dos and don'ts conveyed through gossip will never show up in any student handbook.
    The effects of gossip vary depending on the situation. The next time you feel the urge to spread the latest news, thing about why you want to gossip and what effects your “juicy story” might have.