①大跃进 ②人民公社化运动 ③ ④“两个凡是”思想 ⑤对外开放 ⑥农业生产合作化
ABC.
回族 a 泼水节
傣族 b 开斋节
藏族 c 那达慕大会
蒙古族 d 雪顿节
,这里等式右边是通常的四则运算.请解方程(﹣2)⊗x=1⊗x.

Many people go to school for an education. They learn languages, history, politics, geography, physics, chemistry and mathematics. Others go to school to learn a skill so that theycan make a living.
School education is very important and useful. Yet, no one can learn everything from school. A teacher, no matter how much he knows, cannot teach his students everything they want to know. The teacher's job is to show his students how to learn. He teaches them how to read and how to think. So, much more is to be learned outside school by the students themselves.
It is always more important to know how to study by oneself than to memorize some facts or a formula(公式). It is actually quite easy to learn a certain fact in history or a formula in math. But it is very difficult to use a formula in working out a math problem.
Great scientists before us didn't get everything from school. Their teachers only showed them the way. Edison didn't even finish primary school. But they were all so successful. They invented so many things for mankind. The reason for their success is that they knew how to study. They read books that were not taught at school. They would ask many questions as they read. They did thousands of experiments. They worked hard all their lives, wasting not a single moment. Above all, they knew how to use their brain.
中,点M,N分别是边
,
的中点,点P是对角线
上的动点,连接
,
,
,当
是等腰三角形时,求线段
的长度.小明根据学习函数的经验,对此问题进行了以下探究,请补充完整.
上的不同位置,画图、测量,得到了线段
,
,
的长度的几组值,如下表: | | 0 | 1.0 | 2.0 | 3.0 | 4.0 | 5.0 | 6.0 | 7.0 | 8.0 |
| | 2.5 | 1.8 | 1.4 | 1.8 | 2.5 | 3.3 | 4.2 | 5.2 | 6.2 |
| | 6.2 | 5.2 | 4.2 | 3.3 | 2.5 | 1.8 | 1.4 | 1.8 | 2.5 |
①通过观察(1)中表格,可以得到菱形
的对角线
长为
,菱形
的边长为
;
②在
,
,
的长度这三个量中,确定的长度是自变量,的长度和的长度都是这个自变量的函数.
是等腰三角形时,线段
的长度为.(结果保留一位小数)

材料:20世界30年代,就全球范围看,这是世界经济发展缓慢、充满暴力和反抗的年代, 就中国而言,这又是一个喜忧参半的年代,新民主主义革命曲折发展,民族危机不断加深。人类在黎明前的黑暗中即将迎来第一缕曙光。
B .
C .
D .
B .
C .
D .