已知函数f(x) =2x+1，x∈R.规定：给定一个实数x0，赋值x₁= f(x₀)，若x₁≤255，则继续赋值x₂=" f(x₁)" …，以此类推，若x_n-1≤255，则x_n= f(x_n-1)，否则停止赋值，如果得到xn后停止，则称赋值了n次（n∈N *）.已知赋值k次后该过程停止，则x₀的取值范围是 （）

有人给家兔注射一种可以特异性破坏胰岛B细胞的药物----链脲佐菌素（STZ）进行血糖调节研究，为了准确判断STZ是否成功破坏胰岛B细胞，应（  ）
①在兔饱足状态下       ②在兔空腹状态下       ③测定血液胰岛素含量
④测定尿液是否含糖     ⑤测定血糖含量

    Two brothers worked together on a farm.  One was married and had a large1. The other had no wife yet. Although they lived in different houses, they shared everything they got from their farm.
    One day, the single brother said to himself, "It's not2that we share all the rice. I'm3and I need less than my brother. " So, every night he took a bag of rice from his store-room and4across the field 5their houses, putting it into his brother's store-room.
     At the same time, the married brother thought, "It's not fair to share all the rice. I’m married and I have my wife and children to6me when I am7. However, my brother has no one to take care of his8 " So, each night he also took a bag of rice and put it into his brother's store-room.
    Several months passed by. They found9strange that their rice never became less. Then, one dark night the two brothers ran into each other. Slowly they began to understand what was happening. Their bags fell onto the ground and tears10 their eyes at once.

“四大发明是中华民族的奇迹和骄傲，但罗盘针可以导航也可以看风水；火药可以开矿筑路也可以制造杀人的武器。”就此观点，甲、乙同学展开争论，甲：“四大发明一方面代表了辉煌的成就，另一方面在某种程度上影响了中华民族的发展。”乙：“科学技术能否产生巨大的效益取决于社会环境。”对甲、乙同学的看法，你认为

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有人建议推动街区化，原则上不再建封闭式住宅小区，已建成的住宅小区和单位大院将逐步打开， 实行内部道路公共化。这一动议关涉千家万户，引发广泛讨论。有人认为，推动街区化，可以节约土地，缓解交通压力；有人认为，推动街区化，不利于小区安全；有人认为，推动街区化，将会与中国 传统的生活方式和文化习俗冲突，有利有弊，需慎重推行。对于以上事情，你怎么看？请写一篇文章，表明你的态度，阐述你的看法。

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