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人教版高中数学选修3组合与组合数教学设计
解析:因为减法和除法运算中交换两个数的位置对计算结果有影响,所以属于组合的有2个.答案:B2.若A_n^2=3C_(n"-" 1)^2,则n的值为( )A.4 B.5 C.6 D.7 解析:因为A_n^2=3C_(n"-" 1)^2,所以n(n-1)=(3"(" n"-" 1")(" n"-" 2")" )/2,解得n=6.故选C.答案:C 3.若集合A={a1,a2,a3,a4,a5},则集合A的子集中含有4个元素的子集共有 个. 解析:满足要求的子集中含有4个元素,由集合中元素的无序性,知其子集个数为C_5^4=5.答案:54.平面内有12个点,其中有4个点共线,此外再无任何3点共线,以这些点为顶点,可得多少个不同的三角形?解:(方法一)我们把从共线的4个点中取点的多少作为分类的标准:第1类,共线的4个点中有2个点作为三角形的顶点,共有C_4^2·C_8^1=48(个)不同的三角形;第2类,共线的4个点中有1个点作为三角形的顶点,共有C_4^1·C_8^2=112(个)不同的三角形;第3类,共线的4个点中没有点作为三角形的顶点,共有C_8^3=56(个)不同的三角形.由分类加法计数原理,不同的三角形共有48+112+56=216(个).(方法二 间接法)C_12^3-C_4^3=220-4=216(个).
初二学生国旗下讲话稿——告别童年，走向成熟
大家好！我是来自初二（9）班的吴佩臻，今天我国旗下的讲话题目为“告别童年 走向成熟”两天后，就是儿童节了，首先我在这里祝大家儿童节快乐。而对于我们初二的同学们来说，这是最后一个儿童节，也将标志着我们告别童年，带着早已沸腾在血液中的成熟，早已准备着跳动青春的气息，真正地成为一名青少年，去拥抱五岁的天空。时光荏苒，蓦然回首，这十几年，我们在成长的道路上，印下了一个个或大或小或深或浅的足迹。十几年来，我们用天真烂漫的情怀，编织了一首人生中最难以忘怀的童年之歌。还记得月光下和小伙伴在庭院里洒下的咯咯笑声吗？那是我们快乐的童年。还记得冲刺外校前奔波于各个培优点之间的匆匆身影吗？那是我们紧张忙碌的童年。还记得刚入校时我们无法适应新生活而挂在嘴边的声声抱怨吗？那是我们受挫的童年。
2022年湖北省咸宁市、孝感市中考语文真题（原卷版）
彭德怀接着说：“我正从他家门前经过，停止着观看这种示威。我看这些人一多半已饿个半死，而且我知道这个富人在他的仓里有一万石以上的米。可是他完全拒绝帮助这些饥饿的人们。我激怒起来了，领导着农民攻打并且冲进他的家里。农民运走了他的仓里的一大半粮，食。以后我想到这件事情时，我不知道当时为什么要那样做。我只知道他应该把米卖给穷人的，而且如果他不肯这样做的话，那他们从他这里把米抢走，是很对的。”
2022年湖北省武汉市中考语文真题（原卷版）
却说那悟空别了师父，一筋斗云径转东洋大海，按住云头，分开水道，径至水晶宫前。早惊动龙王出来迎接，接至宫里坐下，礼毕，龙王道：“近闻得大圣难满，失贺！想必是重整仙山，复归古洞矣？”
湖北省随州市2021年中考语文试题（解析版）
位朋友在从莫斯科通往彼得堡的尼古拉铁路的一个站点上邂逅。两个人中一位是胖子，一位是瘦子。胖子刚在站点的餐厅用过午餐，嘴唇油光锃亮，活像两颗熟透了的樱桃。他身上散发出一股烈性葡萄酒和橙花的气息。瘦子呢，刚从车厢里出来，费劲地拖着提箱、大包小包和几只纸板盒子。他的身上则有一股火腿肠和咖啡渣的气息。他的身后，有个尖下巴的瘦女人在东张西望，那是他的妻子，此外还有他的儿子，一位高个子的中学生，眯着一只眼睛。
湖北省荆门市2021年中考语文试题（原卷版）
眼中带出些渴望看到他的光儿；嘴可是张着点，露出点儿冷笑：鼻子纵起些纹缕，折叠着些不屑与急切：眉棱棱着，在一脸的怪粉上显出妖媚而霸道。
湖北省荆州市2021年中考语文试题（原卷版）
蒋介石预料到红军企图渡过长江进入四川，于是从湖北、安徽和江西抽调了大批兵力，用船急速向西运送，企图从北切断红军的进军路线。所有的渡口都有重兵把守；所有的渡船郡被撤到长江北岸；所有的道路都被封锁；大片地区的粮食都被劫掠一空。
湖北省十堰市2021年中考语文试题（解析版）
十七岁那年夏天，父母送我去大学报到。我们住在一个简陋的小旅馆，旅馆对面有一个花坛，母亲在那里第一次看到了一种奇怪的花。小小的五瓣花瓣，组合成一张人的脸谱，有眼睛有鼻子有嘴巴，五官是深紫色，脸膛是浅紫色或嫩黄色。母亲对花的知识匮乏，直接称之为“人脸花”。
湖北省十堰市2021年中考语文试题（原卷版）
不久前，国外某汽车品牌车内摄像头拍摄的一组高清画面引发热议。网友表示，私家车内部属于私密空间，如果在毫不知情的情况下，在车内的一举一动都被摄像头记录下来，甚至上传云端，会让人没有安全感。尽管相关品牌已经作出回应，但尚不足以完全消除人们的疑虑。
湖北省随州市2021年中考语文试题（原卷版）
瘦子一听脸色发白，目瞪口呆，但很快脸色舒展开来，现出喜气洋洋的笑容来，脸上、眼睛里似乎火星四射。他整个人像是蜷缩起来，弯腰弓背，矮了大半截儿……他的手提箱、大包小包和纸板盒全都蜷缩起来，现出条条皱纹来……他妻子的尖嘴巴越发尖了。纳法奈尔挺直了身子，扣上制服上所有的扣子……
2022年湖北省荆州市中考英语真题（解析版）
One night many yearsago, an angry voice woke me up from sleep. It was my drunken (喝醉的) father. Those days, he would always ___11___ home very late. Sometimes, he would also go on to fight with my mom.
2022年湖北省鄂州市中考英语真题（解析版）
Dealing with a nosebleed（鼻出血）mightseem simple. But recently, the British RED Cross asked parents with youngchildren how to help a child with a nosebleed. About 65 percent of parents didnot ____11____the correct action to help.
2022年湖北省武汉市中考英语真题（解析版）
The December day started like any other. Papacame back with his boat full of fish. Mama made breakfast for the family.Seven-year-old Joonas was doing his homework, while his two little brothers ranaround the yard. That day seemed peaceful, but Alejo ____16____ better.
2022年湖北省恩施州中考英语真题（解析版）
Once, herfather took her to the kitchen. He asked Jane to take a potato, an egg ____11____ two spoons of tea leaves. Jane was ____12____, andasked her father, “Do you want me to cook?”
2022年湖北省宜昌市中考英语试题（解析版）
Duringwork hours in Becker’s bread shop, the kitchen is especially quiet except thesound of the machine. The quiet environment is not the result of the strictrules, but because all the workers are deaf. They use sign language tocommunicate with each other from time to time.
2022年湖北省宜昌市中考英语试题（原卷版）
Why do you need hobbies? A study has found thatpeople are more positive (积极的) when they take part in a relaxing activity. ___36___Scientists also think they might be good for your brain.
2022年湖北省十堰市中考英语真题（原卷版）
My arms were shaking and my heart was beating ____19____when I stood at the starting line. ____20____ the endless runway (跑道), I felt like a boatfighting against the wind and rain.
2022年湖北省恩施州中考英语真题（原卷版）
Once, herfather took her to the kitchen. He asked Jane to take a potato, an egg ____11____two spoons of tea leaves. Jane was ____12____, and asked her father, “Doyou want me to cook?”
2022年广西北部湾经济区中考英语真题（解析版）
Ibelieved that I was right and he was wrong, and Tony believed that I was wrongand he was right. Our teacher, a kind and smart lady, decided to teach us alesson. She brought us to the front of the class and placed him on one side ofher desk and me on the other. In the middle of her desk was a large and roundobject. I could clearly see that it was black. The teacher asked us what colorthe object was. “White,” Tony answered. I couldn’t believe he said the objectwas white! “Clearly, it was black!” Another argument started between Tony andme, this time about the color of the object.
2022年广西北部湾经济区中考英语真题（原卷版）
Ibelieved that I was right and he was wrong, and Tony believed that I was wrongand he was right. Our teacher, a kind and smart lady, decided to teach us alesson. She brought us to the front of the class and placed him on one side ofher desk and me on the other. In the middle of her desk was a large and roundobject. I could clearly see that it was black. The teacher asked us what colorthe object was. “White,” Tony answered. I couldn’t believe he said the object waswhite! “Clearly, it was black!” Another argument started between Tony and me,this time about the color of the object.
