掷一枚质地均匀的正方体骰子，前两次抛掷朝上一面点数都是3，那么第三次抛掷朝上一面的点数为3的概率是____．

阅读下列短文，从每小题所给的A、B、C、D四个选项中选出最佳选项。

    Look at the girl. Her name is Lucy. And this lovely girl is her twin sister Lily.1parents are both （两者都）teachers. They work hard.

    Lucy and Lily2at No.4 Middle School. They go to school3Monday to Friday. They have no classes on Saturdays and Sundays. They have breakfast at 6:30. They go to school at 7:00. Classes

    4at eight. They have four5in the morning and three in the afternoon. They have6at 12: 15. At 3:50,they have sports.

    Lucy and Lily study Chinese, math, English, geography, physics, history and other lessons. Lucy's favorite7is music,8it's relaxing. Lily likes science best. She thinks it's difficult 9interesting.

    Their parents like reading. They often read books at home. Their parents are strict(严厉地)with  them, but sometimes they are very kind and friendly to their children. Lucy and Lily love their10 very much.

《史记》载：田忌欲引兵之赵，孙子曰：“今梁赵相攻，轻兵锐卒必竭于外，老弱罢于内。君不若引兵疾走大梁，据其街路，冲其方虚，彼必释赵而自救。是我一举解越之围而收毙魏也。”田忌从之，魏果去邯郸，与齐战于桂陵，大破梁军。这一兵法启示我们(　　)
①人们的准确预见是实践成功的关键    ②要学会在事物联系中寻求最优目标
③只有符合客观实际的认识才起作用    ④一切要以时间、地点、条件为转移

给出下列命题：

①“x²=1”是“x=1”的充分不必要条件；

②“x=﹣1”是“x²﹣3x+2=0”的必要不充分条件；

③命题“∃x∈R，使得x²+x+1＜0”的否定是“∀x∈R，均有x²+x+1≥0”；

④命题“若x=y，则sinx=siny”的逆否命题为真命题；

其中真命题有____ ．（把你认为正确的命题序号都填上）

下列哪组生产方式不符合循环经济模式