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人教版高中數(shù)學(xué)選修3離散型隨機(jī)變量的方差教學(xué)設(shè)計(jì)
3.下結(jié)論.依據(jù)均值和方差做出結(jié)論.跟蹤訓(xùn)練2. A、B兩個(gè)投資項(xiàng)目的利潤(rùn)率分別為隨機(jī)變量X1和X2，根據(jù)市場(chǎng)分析， X1和X2的分布列分別為X1 2% 8% 12% X2 5% 10%P 0.2 0.5 0.3 P 0.8 0.2求：(1)在A、B兩個(gè)項(xiàng)目上各投資100萬(wàn)元， Y1和Y2分別表示投資項(xiàng)目A和B所獲得的利潤(rùn)，求方差D(Y1)和D(Y2)；(2)根據(jù)得到的結(jié)論，對(duì)于投資者有什么建議？ 解：(1)題目可知，投資項(xiàng)目A和B所獲得的利潤(rùn)Y1和Y2的分布列為：Y1 2 8 12 Y2 5 10P 0.2 0.5 0.3 P 0.8 0.2所以 ;; 解：(2) 由(1)可知 ，說(shuō)明投資A項(xiàng)目比投資B項(xiàng)目期望收益要高；同時(shí) ，說(shuō)明投資A項(xiàng)目比投資B項(xiàng)目的實(shí)際收益相對(duì)于期望收益的平均波動(dòng)要更大.因此，對(duì)于追求穩(wěn)定的投資者，投資B項(xiàng)目更合適;而對(duì)于更看重利潤(rùn)并且愿意為了高利潤(rùn)承擔(dān)風(fēng)險(xiǎn)的投資者，投資A項(xiàng)目更合適.
人教版高中數(shù)學(xué)選修3離散型隨機(jī)變量的均值教學(xué)設(shè)計(jì)
對(duì)于離散型隨機(jī)變量，可以由它的概率分布列確定與該隨機(jī)變量相關(guān)事件的概率。但在實(shí)際問(wèn)題中，有時(shí)我們更感興趣的是隨機(jī)變量的某些數(shù)字特征。例如，要了解某班同學(xué)在一次數(shù)學(xué)測(cè)驗(yàn)中的總體水平，很重要的是看平均分；要了解某班同學(xué)數(shù)學(xué)成績(jī)是否“兩極分化”則需要考察這個(gè)班數(shù)學(xué)成績(jī)的方差。我們還常常希望直接通過(guò)數(shù)字來(lái)反映隨機(jī)變量的某個(gè)方面的特征，最常用的有期望與方差.二、 探究新知探究1.甲乙兩名射箭運(yùn)動(dòng)員射中目標(biāo)靶的環(huán)數(shù)的分布列如下表所示：如何比較他們射箭水平的高低呢？環(huán)數(shù)X 7 8 9 10甲射中的概率 0.1 0.2 0.3 0.4乙射中的概率 0.15 0.25 0.4 0.2類似兩組數(shù)據(jù)的比較,首先比較擊中的平均環(huán)數(shù),如果平均環(huán)數(shù)相等，再看穩(wěn)定性.假設(shè)甲射箭n次，射中7環(huán)、8環(huán)、9環(huán)和10環(huán)的頻率分別為：甲n次射箭射中的平均環(huán)數(shù)當(dāng)n足夠大時(shí)，頻率穩(wěn)定于概率，所以x穩(wěn)定于7×0.1+8×0.2+9×0.3+10×0.4=9.即甲射中平均環(huán)數(shù)的穩(wěn)定值(理論平均值)為9,這個(gè)平均值的大小可以反映甲運(yùn)動(dòng)員的射箭水平.同理，乙射中環(huán)數(shù)的平均值為7×0.15+8×0.25+9×0.4+10×0.2=8.65.
新人教版高中英語(yǔ)選修2Unit 3 Food and Culture-Discovering useful structures教學(xué)設(shè)計(jì)
The newspaper reported more than 100 people had been killed in the thunderstorm.報(bào)紙報(bào)道說(shuō)有一百多人在暴風(fēng)雨中喪生。(2)before、when、by the time、until、after、once等引導(dǎo)的時(shí)間狀語(yǔ)從句的謂語(yǔ)是一般過(guò)去時(shí)，以及by、before后面接過(guò)去的時(shí)間時(shí)，主句動(dòng)作發(fā)生在從句的動(dòng)作或過(guò)去的時(shí)間之前且表示被動(dòng)時(shí)，要用過(guò)去完成時(shí)的被動(dòng)語(yǔ)態(tài)。By the time my brother was 10, he had been sent to Italy.我弟弟10歲前就已經(jīng)被送到意大利了。Tons of rice had been produced by the end of last month. 到上月底已生產(chǎn)了好幾噸大米。(3) It was the first/second/last ... time that ...句中that引導(dǎo)的定語(yǔ)從句中，主語(yǔ)與謂語(yǔ)構(gòu)成被動(dòng)關(guān)系時(shí)，要用過(guò)去完成時(shí)的被動(dòng)語(yǔ)態(tài)。It was the first time that I had seen the night fact to face in one and a half years. 這是我一年半以來(lái)第一次親眼目睹夜晚的景色。(4)在虛擬語(yǔ)氣中，條件句表示與過(guò)去事實(shí)相反，且主語(yǔ)與謂語(yǔ)構(gòu)成被動(dòng)關(guān)系時(shí)，要用過(guò)去完成時(shí)的被動(dòng)語(yǔ)態(tài)。If I had been instructed by him earlier, I would have finished the task.如果我早一點(diǎn)得到他的指示，我早就完成這項(xiàng)任務(wù)了。If I had hurried, I wouldn't have missed the train.如果我快點(diǎn)的話，我就不會(huì)誤了火車。If you had been at the party, you would have met him. 如果你去了晚會(huì)，你就會(huì)見(jiàn)到他的。
新人教版高中英語(yǔ)選修2Unit 3 Food and Culture-Reading and thinking教學(xué)設(shè)計(jì)
The discourse explores the link between food and culture from a foreign’s perspective and it records some authentic Chinese food and illustrates the cultural meaning, gerography features and historic tradition that the food reflects. It is aimed to lead students to understand and think about the connection between food and culture. While teaching, the teacher should instruct students to find out the writing order and the writer’s experieces and feelings towards Chinese food and culture.1.Guide the students to read the text, sort out the information and dig out the topic.2.Understand the cultural connotation, regional characteristics and historical tradition of Chinese cuisine3.Understand and explore the relationship between food and people's personality4.Guide the students to use the cohesive words in the text5.Lead students to accurately grasp the real meaning of the information and improve the overall understanding ability by understanding the implied meaning behind the text.1. Enable the Ss to understand the structure and the writing style of the passage well.2. Lead the Ss to understand and think further about the connection between food and geography and local character traits.Step1: Prediction before reading. Before you read, look at the title, and the picture. What do you think this article is about?keys:It is about various culture and cuisine about a place or some countries.
關(guān)于總工會(huì)社會(huì)聯(lián)絡(luò)部社會(huì)組織處處長(zhǎng)掛職鍛煉工作總結(jié)
二是樹(shù)立問(wèn)題意識(shí)。問(wèn)題是事物矛盾的直觀反映，是實(shí)踐發(fā)展的有力引導(dǎo)，抓住了主要問(wèn)題，就找到了工作的著力點(diǎn)和突破口。實(shí)踐中有什么問(wèn)題，我們?cè)诠ぷ髦芯鸵芯渴裁磫?wèn)題，努力解決什么問(wèn)題。這是最樸實(shí)的方法論。比如，關(guān)于簡(jiǎn)化報(bào)表的問(wèn)題。在調(diào)查研究中，基層同志反映，工會(huì)系統(tǒng)數(shù)據(jù)庫(kù)要整合共享，不能都分頭管理，多頭要數(shù)據(jù)，重復(fù)要數(shù)據(jù)，還有大量的日常檢查填表、統(tǒng)計(jì)報(bào)表，基層不堪重負(fù)，影響隊(duì)伍力量辦實(shí)事，“填表不等于工作”，實(shí)干才能服務(wù)職工。三是注重基層導(dǎo)向?；鶎邮枪?huì)全部工作的基礎(chǔ)。×市總工會(huì)高度重視基層，率先在鄉(xiāng)鎮(zhèn)街道全部建立總工會(huì)，率先明確鄉(xiāng)鎮(zhèn)街道總工會(huì)經(jīng)費(fèi)留成×％，率先在鄉(xiāng)鎮(zhèn)街道全部建立工會(huì)服務(wù)站，并由市區(qū)兩級(jí)工會(huì)分擔(dān)聘用專職工會(huì)社會(huì)工作者，有了一支專門的基層工會(huì)工作者隊(duì)伍，保障了基層工會(huì)作用發(fā)揮。做實(shí)基層，夯實(shí)基礎(chǔ)，工作才能落到實(shí)處，工會(huì)才能扎根職工群眾之中。
人教版高中數(shù)學(xué)選修3一元線性回歸模型及其應(yīng)用教學(xué)設(shè)計(jì)
1.確定研究對(duì)象，明確哪個(gè)是解釋變量，哪個(gè)是響應(yīng)變量；2.由經(jīng)驗(yàn)確定非線性經(jīng)驗(yàn)回歸方程的模型；3.通過(guò)變換，將非線性經(jīng)驗(yàn)回歸模型轉(zhuǎn)化為線性經(jīng)驗(yàn)回歸模型；4.按照公式計(jì)算經(jīng)驗(yàn)回歸方程中的參數(shù)，得到經(jīng)驗(yàn)回歸方程；5.消去新元，得到非線性經(jīng)驗(yàn)回歸方程；6.得出結(jié)果后分析殘差圖是否有異常 ．跟蹤訓(xùn)練1.一只藥用昆蟲的產(chǎn)卵數(shù)y與一定范圍內(nèi)的溫度x有關(guān)，現(xiàn)收集了6組觀測(cè)數(shù)據(jù)列于表中： 經(jīng)計(jì)算得： 線性回歸殘差的平方和: ∑_(i=1)^6?〖(y_i-(y_i ) ?)〗^2=236,64,e^8.0605≈3167.其中 分別為觀測(cè)數(shù)據(jù)中的溫度和產(chǎn)卵數(shù)，i=1,2,3,4,5,6.(1)若用線性回歸模型擬合，求y關(guān)于x的回歸方程 (精確到0.1）；(2)若用非線性回歸模型擬合，求得y關(guān)于x回歸方程為 且相關(guān)指數(shù)R2＝0.9522． ①試與(1)中的線性回歸模型相比較，用R2說(shuō)明哪種模型的擬合效果更好 ?②用擬合效果好的模型預(yù)測(cè)溫度為35℃時(shí)該種藥用昆蟲的產(chǎn)卵數(shù).(結(jié)果取整數(shù)).
人教版高中數(shù)學(xué)選修3離散型隨機(jī)變量及其分布列(1)教學(xué)設(shè)計(jì)
4.寫出下列隨機(jī)變量可能取的值，并說(shuō)明隨機(jī)變量所取的值表示的隨機(jī)試驗(yàn)的結(jié)果．(1)一個(gè)袋中裝有8個(gè)紅球，3個(gè)白球，從中任取5個(gè)球，其中所含白球的個(gè)數(shù)為X.(2)一個(gè)袋中有5個(gè)同樣大小的黑球，編號(hào)為1,2,3,4,5，從中任取3個(gè)球，取出的球的最大號(hào)碼記為X.(3). 在本例(1)條件下，規(guī)定取出一個(gè)紅球贏2元，而每取出一個(gè)白球輸1元，以ξ表示贏得的錢數(shù)，結(jié)果如何？[解] (1)X可取0,1,2,3.X＝0表示取5個(gè)球全是紅球；X＝1表示取1個(gè)白球，4個(gè)紅球；X＝2表示取2個(gè)白球，3個(gè)紅球；X＝3表示取3個(gè)白球，2個(gè)紅球．(2)X可取3,4,5.X＝3表示取出的球編號(hào)為1,2,3；X＝4表示取出的球編號(hào)為1,2,4；1,3,4或2,3,4.X＝5表示取出的球編號(hào)為1,2,5；1,3,5；1,4,5；2,3,5；2,4,5或3,4,5.(3) ξ＝10表示取5個(gè)球全是紅球；ξ＝7表示取1個(gè)白球，4個(gè)紅球；ξ＝4表示取2個(gè)白球，3個(gè)紅球；ξ＝1表示取3個(gè)白球，2個(gè)紅球．
人教版高中數(shù)學(xué)選修3分類變量與列聯(lián)表教學(xué)設(shè)計(jì)
一、 問(wèn)題導(dǎo)學(xué)前面兩節(jié)所討論的變量,如人的身高、樹(shù)的胸徑、樹(shù)的高度、短跑100m世界紀(jì)錄和創(chuàng)紀(jì)錄的時(shí)間等,都是數(shù)值變量,數(shù)值變量的取值為實(shí)數(shù).其大小和運(yùn)算都有實(shí)際含義.在現(xiàn)實(shí)生活中,人們經(jīng)常需要回答一定范圍內(nèi)的兩種現(xiàn)象或性質(zhì)之間是否存在關(guān)聯(lián)性或相互影響的問(wèn)題.例如,就讀不同學(xué)校是否對(duì)學(xué)生的成績(jī)有影響,不同班級(jí)學(xué)生用于體育鍛煉的時(shí)間是否有差別,吸煙是否會(huì)增加患肺癌的風(fēng)險(xiǎn),等等,本節(jié)將要學(xué)習(xí)的獨(dú)立性檢驗(yàn)方法為我們提供了解決這類問(wèn)題的方案。在討論上述問(wèn)題時(shí),為了表述方便,我們經(jīng)常會(huì)使用一種特殊的隨機(jī)變量,以區(qū)別不同的現(xiàn)象或性質(zhì),這類隨機(jī)變量稱為分類變量.分類變量的取值可以用實(shí)數(shù)表示,例如,學(xué)生所在的班級(jí)可以用1,2,3等表示,男性、女性可以用1,0表示,等等.在很多時(shí)候,這些數(shù)值只作為編號(hào)使用,并沒(méi)有通常的大小和運(yùn)算意義,本節(jié)我們主要討論取值于{0,1}的分類變量的關(guān)聯(lián)性問(wèn)題.
人教版高中數(shù)學(xué)選修3離散型隨機(jī)變量及其分布列(2)教學(xué)設(shè)計(jì)
溫故知新 1.離散型隨機(jī)變量的定義可能取值為有限個(gè)或可以一一列舉的隨機(jī)變量,我們稱為離散型隨機(jī)變量.通常用大寫英文字母表示隨機(jī)變量,例如X,Y,Z;用小寫英文字母表示隨機(jī)變量的取值,例如x,y,z.隨機(jī)變量的特點(diǎn): 試驗(yàn)之前可以判斷其可能出現(xiàn)的所有值，在試驗(yàn)之前不可能確定取何值；可以用數(shù)字表示2、隨機(jī)變量的分類①離散型隨機(jī)變量:X的取值可一、一列出；②連續(xù)型隨機(jī)變量:X可以取某個(gè)區(qū)間內(nèi)的一切值隨機(jī)變量將隨機(jī)事件的結(jié)果數(shù)量化．3、古典概型:①試驗(yàn)中所有可能出現(xiàn)的基本事件只有有限個(gè)；②每個(gè)基本事件出現(xiàn)的可能性相等。二、探究新知探究1.拋擲一枚骰子,所得的點(diǎn)數(shù)X有哪些值？取每個(gè)值的概率是多少？ 因?yàn)閄取值范圍是{1，2，3，4，5，6}而且"P(X=m)"=1/6,m=1,2,3,4,5,6.因此X分布列如下表所示
新人教版高中英語(yǔ)選修2Unit 1 Science and Scientists-Reading and thinking教學(xué)設(shè)計(jì)
Step 5： After learning the text, discuss with your peers about the following questions:1.John Snow believed Idea 2 was right. How did he finally prove it?2. Do you think John Snow would have solved this problem without the map?3. Cholera is a 19th century disease. What disease do you think is similar to cholera today?SARS and Covid-19 because they are both deadly and fatally infectious, have an unknown cause and need serious public health care to solve them urgently.keys:1. John Snow finally proved his idea because he found an outbreak that was clearly related to cholera, collected information and was able to tie cases outside the area to the polluted water.2. No. The map helped John Snow organize his ideas. He was able to identify those households that had had many deaths and check their water-drinking habits. He identified those houses that had had no deaths and surveyed their drinking habits. The evidence clearly pointed to the polluted water being the cause.3. SARS and Covid-19 because they are both deadly and fatally infectious, have an unknown cause and need serious public health care to solve them urgently.Step 6: Consolidate what you have learned by filling in the blanks:John Snow was a well-known _1___ in London in the _2__ century. He wanted to find the _3_____ of cholera in order to help people ___4_____ it. In 1854 when a cholera __5__ London, he began to gather information. He ___6__ on a map ___7___ all the dead people had lived and he found that many people who had ___8____ (drink) the dirty water from the __9____ died. So he decided that the polluted water ___10____ cholera. He suggested that the ___11__ of all water supplies should be _12______ and new methods of dealing with ____13___ water be found. Finally, “King Cholera” was __14_____.Keys: 1. doctor 2. 19th 3.cause 4.infected with 5.hit 6.marked 7.where 8.drunk 9.pump 10.carried 11.source 12.examined 13.polluted 14.defeatedHomework: Retell the text after class and preview its language points
新人教版高中英語(yǔ)選修2Unit 2 Bridging Cultures-Discovering useful structures教學(xué)設(shè)計(jì)
The grammar of this unit is designed to review noun clauses. Sentences that use nouns in a sentence are called noun clauses. Nominal clauses can act as subject, object, predicate, appositive and other components in compound sentences. According to the above-mentioned different grammatical functions, nominal clauses are divided into subject clause, object clause, predicate clause and appositive clause. In this unit, we will review the three kinds of nominal clauses. Appositive clauses are not required to be mastered in the optional compulsory stage, so they are not involved.1. Guide the students to judge the compound sentences and determine the composition of the clauses in the sentence.2. Instruct students to try to learn grammar by generalizing grammar rules, controlling written practice, and semi-open oral output.3. Inspire the students to systematize the function and usage of noun clause1.Instruct students to try to learn grammar by generalizing grammar rules, controlling written practice, and semi-open oral output.2.Inspire the students to systematize the function and usage of noun clauseStep1: The teacher ask studetns to find out more nominal clauses from the reading passage and udnerline the nominal clauses.
新人教版高中英語(yǔ)選修2Unit 5 First Aid-Discovering useful structures教學(xué)設(shè)計(jì)
You have no excuse for not going.你沒(méi)有理由不去。He was punished for not having finished his homework.他因未完成作業(yè)而受到懲罰。2．動(dòng)詞ing形式復(fù)合結(jié)構(gòu)由物主代詞或人稱代詞賓格、名詞所有格或普通格加動(dòng)詞ing，即“sb./sb.'s＋doing”構(gòu)成。動(dòng)詞ing形式的復(fù)合結(jié)構(gòu)實(shí)際上是給動(dòng)詞ing形式加了一個(gè)邏輯主語(yǔ)。動(dòng)詞ing形式的復(fù)合結(jié)構(gòu)有四種形式：①形容詞性物主代詞＋動(dòng)詞ing②名詞所有格＋動(dòng)詞ing③代詞賓格＋動(dòng)詞ing④名詞＋動(dòng)詞ingHer coming to help encouraged all of us.她來(lái)幫忙鼓舞了我們所有人。The baby was made awake by the door suddenly shutting.這個(gè)嬰兒被突然的關(guān)門聲吵醒了。Can you imagine him/Jack cooking at home?你能想象他/杰克在家做飯的樣子嗎？無(wú)生命名詞無(wú)論是作主語(yǔ)還是作賓語(yǔ)都不能用第②種形式。Tom's winning first prize last year impressed me a lot.湯姆去年得了一等獎(jiǎng)使我印象深刻。Do you mind my/me/Jack's/Jack leaving now?你介意我/杰克現(xiàn)在離開(kāi)嗎？Excuse me for my not coming on time．很抱歉我沒(méi)能按時(shí)來(lái)。His father's being ill made him worried.他父親病了，他很擔(dān)心。We are looking forward to the singer's/the singer to give us a concert.我們盼望著這位歌手來(lái)給我們舉辦一場(chǎng)演唱會(huì)。
新人教版高中英語(yǔ)選修2Unit 1 Science and Scientists-Discovering useful structures教學(xué)設(shè)計(jì)
The grammatical structure of this unit is predicative clause. Like object clause and subject clause, predicative clause is one of Nominal Clauses. The leading words of predicative clauses are that, what, how, what, where, as if, because, etc.The design of teaching activities aims to guide students to perceive the structural features of predicative clauses and think about their ideographic functions. Beyond that, students should be guided to use this grammar in the context apporpriately and flexibly.1. Enable the Ss to master the usage of the predicative clauses in this unit.2. Enable the Ss to use the predicative patterns flexibly.3. Train the Ss to apply some skills by doing the relevant exercises.1.Guide students to perceive the structural features of predicative clauses and think about their ideographic functions.2.Strengthen students' ability of using predicative clauses in context, but also cultivate their ability of text analysis and logical reasoning competence.Step1: Underline all the examples in the reading passage, where noun clauses are used as the predicative. Then state their meaning and functions.1) One theory was that bad air caused the disease.2) Another theory was that cholera was caused by an infection from germs in food or water.3) The truth was that the water from the Broad Street had been infected by waste.Sum up the rules of grammar:1. 以上黑體部分在句中作表語(yǔ)。2. 句1、2、3中的that在從句中不作成分，只起連接作用。 Step2: Review the basic components of predicative clauses1.Definition
新人教版高中英語(yǔ)選修2Unit 4 Journey Across a Vast Land教學(xué)設(shè)計(jì)
當(dāng)孩子們由父母陪同時(shí)，他們才被允許進(jìn)入這個(gè)運(yùn)動(dòng)場(chǎng)。3．過(guò)去分詞(短語(yǔ))作狀語(yǔ)時(shí)的幾種特殊情況(1)過(guò)去分詞(短語(yǔ))在句中作時(shí)間、條件、原因、讓步狀語(yǔ)時(shí)，相當(dāng)于對(duì)應(yīng)的時(shí)間、條件、原因及讓步狀語(yǔ)從句。Seen from the top of the mountain (＝When it is seen from the top of the mountain), the whole town looks more beautiful.從山頂上看，整個(gè)城市看起來(lái)更美了。Given ten more minutes (＝If we are given ten more minutes), we will finish the work perfectly.如果多給十分鐘，我們會(huì)完美地完成這項(xiàng)工作。Greatly touched by his words (＝Because she was greatly touched by his words), she was full of tears.由于被他的話深深地感動(dòng)，她滿眼淚花。Warned of the storm (＝Though they were warned of the storm), the farmers were still working on the farm.盡管被警告了風(fēng)暴的到來(lái)，但農(nóng)民們?nèi)栽谵r(nóng)場(chǎng)干活。(2)過(guò)去分詞(短語(yǔ))在句中作伴隨、方式等狀語(yǔ)時(shí)，可改為句子的并列謂語(yǔ)或改為并列分句。The teacher came into the room, followed by two students (＝and was followed by two students)．后面跟著兩個(gè)學(xué)生，老師走進(jìn)了房間。He spent the whole afternoon, accompanied by his mom(＝and was accompanied by his mom)．他由母親陪著度過(guò)了一整個(gè)下午。
新人教版高中英語(yǔ)選修2Unit 1 Science and Scientists-Learning about Language教學(xué)設(shè)計(jì)
Step 7: complete the discourse according to the grammar rules.Cholera used to be one of the most 1.__________ (fear) diseases in the world. In the early 19th century, _2_________ an outbreak of cholera hit Europe, millions of people died. But neither its cause, 3__________ its cure was understood. A British doctor, John Snow, wanted to solve the problem and he knew that cholera would not be controlled _4_________ its cause was found. In general, there were two contradictory theories 5 __________ explained how cholera spread. The first suggested that bad air caused the disease. The second was that cholera was caused by an _6_________(infect) from germs in food or water. John Snow thought that the second theory was correct but he needed proof. So when another outbreak of cholera hit London in 1854, he began to investigate. Later, with all the evidence he _7_________ (gather), John Snow was able to announce that the pump water carried cholera germs. Therefore, he had the handle of the pump _8_________ (remove) so that it couldn't be used. Through his intervention，the disease was stopped in its tracks. What is more, John Snow found that some companies sold water from the River Thames that __9__________________ (pollute) by raw waste. The people who drank this water were much more likely _10_________ (get) cholera than those who drank pure or boiled water. Through John Snow's efforts, the _11_________ (threaten) of cholera around the world saw a substantial increase. Keys： 1.feared 2.when 3. nor 4.unless 5.that/which 6.infection 7.had gathered 8.removed 9.was polluted 10.to get 11. threat
新人教版高中英語(yǔ)選修2Unit 1 Science and Scientists-Using langauge教學(xué)設(shè)計(jì)
This happens because the dish soap molecules have a strong negative charge, and the milk molecules have a strong positive charge. Like magnets, these molecules are attracted to each other, and so they appear to move around on the plate, taking the food coloring with them, making it look like the colors are quickly moving to escape from the soap.Listening text:? Judy: Oh, I'm so sorry that you were ill and couldn't come with us on our field trip. How are you feeling now? Better?? Bill: Much better, thanks. But how was it?? Judy: Wonderful! I especially liked an area of the museum called Light Games.it was really cool. They had a hall of mirrors where I could see myself reflected thousands of times!? Bill: A hall of mirrors can be a lot of fun. What else did they have?? Judy: Well, they had an experiment where we looked at a blue screen for a while, and then suddenly we could see tiny bright lights moving around on it. You'll never guess what those bright lights were!? Bill: Come on, tell me!? Judy: They were our own blood cells. For some reason, our eyes play tricks on us when we look at a blue screen, and we can see our own blood cells moving around like little lights! But there was another thing I liked better. I stood in front of a white light, and it cast different shadows of me in every color of the rainbow!? Bill: Oh, I wish I had been there. Tell me more!? Judy: Well, they had another area for sound. They had a giant piano keyboard that you could use your feet to play. But then, instead of playing the sounds of a piano, it played the voices of classical singers! Then they had a giant dish, and when you spoke into it, it reflected the sound back and made it louder. You could use it to speak in a whisper to someone 17 meters away.? Bill: It all sounds so cool. I wish I could have gone with you? Judy: I know, but we can go together this weekend. I'd love to go there again!? Bill: That sounds like a great idea!
人教版高中數(shù)學(xué)選修3分類加法計(jì)數(shù)原理與分步乘法計(jì)數(shù)原理(2)教學(xué)設(shè)計(jì)
當(dāng)A,C顏色相同時(shí),先染P有4種方法,再染A,C有3種方法,然后染B有2種方法,最后染D也有2種方法.根據(jù)分步乘法計(jì)數(shù)原理知,共有4×3×2×2=48(種)方法;當(dāng)A,C顏色不相同時(shí),先染P有4種方法,再染A有3種方法,然后染C有2種方法,最后染B,D都有1種方法.根據(jù)分步乘法計(jì)數(shù)原理知,共有4×3×2×1×1=24(種)方法.綜上,共有48+24=72(種)方法.故選B.答案:B5.某藝術(shù)小組有9人,每人至少會(huì)鋼琴和小號(hào)中的一種樂(lè)器,其中7人會(huì)鋼琴,3人會(huì)小號(hào),從中選出會(huì)鋼琴與會(huì)小號(hào)的各1人,有多少種不同的選法?解:由題意可知,在藝術(shù)小組9人中,有且僅有1人既會(huì)鋼琴又會(huì)小號(hào)(把該人記為甲),只會(huì)鋼琴的有6人,只會(huì)小號(hào)的有2人.把從中選出會(huì)鋼琴與會(huì)小號(hào)各1人的方法分為兩類.第1類,甲入選,另1人只需從其他8人中任選1人,故這類選法共8種;第2類,甲不入選,則會(huì)鋼琴的只能從6個(gè)只會(huì)鋼琴的人中選出,有6種不同的選法,會(huì)小號(hào)的也只能從只會(huì)小號(hào)的2人中選出,有2種不同的選法,所以這類選法共有6×2=12(種).因此共有8+12=20(種)不同的選法.
人教版高中數(shù)學(xué)選修3分類加法計(jì)數(shù)原理與分步乘法計(jì)數(shù)原理(1)教學(xué)設(shè)計(jì)
問(wèn)題1. 用一個(gè)大寫的英文字母或一個(gè)阿拉伯?dāng)?shù)字給教室里的一個(gè)座位編號(hào)，總共能編出多少種不同的號(hào)碼？因?yàn)橛⑽淖帜腹灿?6個(gè)，阿拉伯?dāng)?shù)字共有10個(gè)，所以總共可以編出26+10=36種不同的號(hào)碼.問(wèn)題2.你能說(shuō)說(shuō)這個(gè)問(wèn)題的特征嗎？上述計(jì)數(shù)過(guò)程的基本環(huán)節(jié)是：（1）確定分類標(biāo)準(zhǔn)，根據(jù)問(wèn)題條件分為字母號(hào)碼和數(shù)字號(hào)碼兩類；（2）分別計(jì)算各類號(hào)碼的個(gè)數(shù)；（3）各類號(hào)碼的個(gè)數(shù)相加，得出所有號(hào)碼的個(gè)數(shù).你能舉出一些生活中類似的例子嗎？一般地，有如下分類加法計(jì)數(shù)原理：完成一件事，有兩類辦法. 在第1類辦法中有m種不同的方法，在第2類方法中有n種不同的方法，則完成這件事共有:N= m+n種不同的方法.二、典例解析例1.在填寫高考志愿時(shí)，一名高中畢業(yè)生了解到，A,B兩所大學(xué)各有一些自己感興趣的強(qiáng)項(xiàng)專業(yè)，如表，
組織觀看地震科普攜手同行心得體會(huì)
如果在野外，一定要避開(kāi)陡崖，防止掉下山。還有要預(yù)防山體滑坡，以免滑下去。如果在學(xué)校，一定要聽(tīng)從老師的指揮，躲到課桌下，注意保護(hù)頭部，如果在上體育課，要避免高大的建筑物，不要被砸傷。如果在電影院，要躲在觀看椅底下避震，要避開(kāi)掛在天花板上的燈、空調(diào)的懸掛物，用東西保護(hù)頭部，聽(tīng)從指揮人員指揮撤離現(xiàn)場(chǎng)。在商場(chǎng)發(fā)生了地震，要避開(kāi)玻璃柜，避開(kāi)貨物、廣告牌、燈等物品。如果在公共汽車內(nèi)，要躲在椅子底下或蹲下，要穩(wěn)住重心，扶好扶手。如果你被壓在廢墟的底下，這時(shí)候，你不要盲目亂動(dòng)，要冷靜，先把手抽出來(lái)，慢慢地挪動(dòng)廢墟，先保持呼吸順暢，再想辦法呼吸，喊人員來(lái)救你。
組織觀看地震科普攜手同行心得體會(huì)
如果在野外，一定要避開(kāi)陡崖，防止掉下山。還有要預(yù)防山體滑坡，以免滑下去。如果在學(xué)校，一定要聽(tīng)從老師的指揮，躲到課桌下，注意保護(hù)頭部，如果在上體育課，要避免高大的建筑物，不要被砸傷。如果在電影院，要躲在觀看椅底下避震，要避開(kāi)掛在天花板上的燈、空調(diào)的懸掛物，用東西保護(hù)頭部，聽(tīng)從指揮人員指揮撤離現(xiàn)場(chǎng)。在商場(chǎng)發(fā)生了地震，要避開(kāi)玻璃柜，避開(kāi)貨物、廣告牌、燈等物品。如果在公共汽車內(nèi)，要躲在椅子底下或蹲下，要穩(wěn)住重心，扶好扶手。如果你被壓在廢墟的底下，這時(shí)候，你不要盲目亂動(dòng)，要冷靜，先把手抽出來(lái)，慢慢地挪動(dòng)廢墟，先保持呼吸順暢，再想辦法呼吸，喊人員來(lái)救你。