
解析:由分式有意義的條件得3x-1≠0,解得x≠13.則分式無意義的條件是x=13,故選C.方法總結:分式無意義的條件是分母等于0.【類型三】 分式值為0的條件若使分式x2-1x+1的值為零,則x的值為()A.-1 B.1或-1C.1 D.1和-1解析:由題意得x2-1=0且x+1≠0,解得x=1,故選C.方法總結:分式的值為零的條件:(1)分子為0;(2)分母不為0.這兩個條件缺一不可.三、板書設計1.分式的概念:一般地,如果A、B表示兩個整式,并且B中含有字母,那么式子AB叫做分式.2.分式AB有無意義的條件:當B≠0時,分式有意義;當B=0時,分式無意義.3.分式AB值為0的條件:當A=0,B≠0時,分式的值為0.本節(jié)采取的教學方法是引導學生獨立思考、小組合作,完成對分式概念及意義的自主探索.提出問題讓學生解決,問題由易到難,層層深入,既復習了舊知識又在類比過程中獲得了解決新知識的途徑.在這一環(huán)節(jié)提問應注意循序性,先易后難、由簡到繁、層層遞進,臺階式的提問使問題解決水到渠成.

(六)說教學策略1.專題性海量的媒介信息必須加以選擇或者整合,以項目為依據(jù),進行信息篩選,形成專題性閱讀與交流;培養(yǎng)學生對文本信息“化零為整”的能力,提升跨媒介閱讀與交流學習的充實感。2.情境化情境教學應指向?qū)W生的應用,建構富有符合時代氣息的內(nèi)容,與生活經(jīng)驗更加貼合,對學生的語言建構與運用有所提升,在情境中能夠有效地進行交流。3.任務化以任務為導向的序列化學習,可以為學生構建學習路線圖、學習框架等具體任務引導;或以跨媒介的認識與應用為任務的設置引導;甚至以閱讀和交流作為序列化安排的實踐引導。4.整合性跨媒介閱讀與交流是結合線上線下的資源,形成新的“超媒介”,也能實現(xiàn)對信息進行“深加工”,多種媒介的信息整合只為一個核心教學內(nèi)容服務。5.互文性語言文字是語文之生命,我們是立足于語言文字的探討,音樂、圖像、視頻等文本與傳統(tǒng)語言文字文本形成互文,觸發(fā)學生對學習內(nèi)容立體化和具體化的感悟,提升學生的審美能力。

“用計算器計算”是江蘇國標版四年級上冊數(shù)學第十一單元的教學內(nèi)容這部分內(nèi)容是在學生熟練掌握了整數(shù)的四則計算法則及兩步混合運算的基礎上進行教學。通過學習使學生可以借助計算器進行較大數(shù)目的四則運算并借助計算器來探索有關規(guī)律有利于幫助學生形成初步的探索和解決問題的能力。 本單元內(nèi)容分兩段安排,第一段先認識計算器了解計算器的基本功能和操作方法再學習用計算器進行四則計算的方法。第二段教學用計算器進行兩步混合運算并安排了練習十。教材在“想想做做”和練習十中還編排了一些探索數(shù)學規(guī)律的趣題并通過“你知道嗎”介紹“改錯鍵”等常用的功能鍵以及有關計算工具發(fā)展的歷史讓學生了解計算工具的演變過程感受人類科技的進步與發(fā)展。最后教材還安排了實踐活動《一億有多大》幫助學生形成良好的數(shù)感。本單元分四課時完成今天我說的是第一課時。

三、影響區(qū)域環(huán)境說明:環(huán)境是旅游業(yè)的基礎,旅游對環(huán)境保護具有促進作用。世界上很多國家在發(fā)展旅游業(yè)的同時,都很重視對旅游資源和環(huán)境的保護,以實現(xiàn)旅游業(yè)的可持續(xù)發(fā)展。旅游業(yè)的發(fā)展對環(huán)境也有消極作用,如果旅游與環(huán)境的關系不處理好,環(huán)境也會朝著惡化的方向發(fā)展。圖1.10古建修復圖1.10對比顯示古建筑修復前后景觀的變化,說明旅游業(yè)的發(fā)展有利于文物古跡和古建筑的保護。討論:1.列舉旅游業(yè)發(fā)展有利于環(huán)境的措施。提示:建立各種自然保護區(qū)、申報歷史文物保護單位等措施都有利于保護旅游環(huán)境。2.舉例說明旅游對環(huán)境的消極作用。提示:旅游對環(huán)境的消極作用主要表現(xiàn)在:由于對旅游資源開發(fā)建設不當或失誤,使生態(tài)環(huán)境惡化;由于大量游客的涌入,排放的各類廢棄物超過了環(huán)境自凈能力而造成環(huán)境污染;由于大量游客的接觸或不文明行為引起的對風景、文物的破壞等。

方法總結:(1)若被開方數(shù)中含有負因數(shù),則應先化成正因數(shù),如(3)題.(2)將二次根式盡量化簡,使被開方數(shù)(式)中不含能開得盡方的因數(shù)(因式),即化為最簡二次根式(后面學到).探究點三:最簡二次根式在二次根式8a,c9,a2+b2,a2中,最簡二次根式共有()A.1個 B.2個C.3個 D.4個解析:8a中有因數(shù)4;c9中有分母9;a3中有因式a2.故最簡二次根式只有a2+b2.故選A.方法總結:只需檢驗被開方數(shù)是否還有分母,是否還有能開得盡方的因數(shù)或因式.三、板書設計二次根式定義形如a(a≥0)的式子有意義的條件:a≥0性質(zhì):(a)2=a(a≥0),a2=a(a≥0)最簡二次根式本節(jié)經(jīng)歷從具體實例到一般規(guī)律的探究過程,運用類比的方法,得出實數(shù)運算律和運算法則,使學生清楚新舊知識的區(qū)別和聯(lián)系,加深學生對運算法則的理解,能否根據(jù)問題的特點,選擇合理、簡便的算法,能否確認結果的合理性等等.

屬于此類問題一般有以下三種情況①具體數(shù)字,此時化簡的條件已暗中給定,②恒為非負值或根據(jù)題中的隱含條件,如(1)小題。③給出明確的條件,如(2)小題。第二類,需討論后再化簡。當題目中給定的條件不能判定絕對值符號內(nèi)代數(shù)式值的符號時,則需討論后化簡,如(4)小題。例3.已知a+b=-6,ab=5,求 的值。解:∵ab=5>0,∴a,b同號,又∵a+b=-6<0,∴a<0,b<0∴ .說明:此題中的隱含條件a<0,b<0不能忽視。否則會出現(xiàn)錯誤。例4.化簡: 解:原式=|x-6|-|1+2x|+|x+5|令x-6=0,得x=6,令1+2x=0,得 ,令x+5=0,得x=-5.這樣x=6, ,x=-5,把數(shù)軸分成四段(四個區(qū)間)在這五段里分別討論如下:當x≥6時,原式=(x-6)-(1+2x)+(x+5)=-2.當 時,原式=-(x-6)-(1+2x)+(x+5)=-2x+10.當 時,原式=-(x-6)-[-(1+2x)]+(x+5)=2x+12.當x<-5時,原式=-(x-6)+(1+2x)-(x+5)=2.說明:利用公式 ,如果絕對值符號里面的代數(shù)式的值的符號無法決定,則需要討論。方法是:令每一個絕對值內(nèi)的代數(shù)式為零,求出對應的“零點”,再用這些“零點”把數(shù)軸分成若干個區(qū)間,再在每個區(qū)間內(nèi)進行化簡。

評價:這段話表明傅雷朋友的角色。他把孩子當成朋友,為人生得一知己而感到興奮、自豪。在讀這段話時聲音應洪亮,感情應充沛。小結:我們組還發(fā)現(xiàn)傅雷對傅聰?shù)姆Q呼有很多,如聰、聰兒、孩子、親愛的聰、親愛的孩子。有時兩個同時用,比如“聰,親愛的孩子!”一直以來,我們都覺得父愛不善表達,可是傅雷的這些親昵直白的稱呼表達了他對傅聰?shù)膼?,是這么的溫柔,如慈母一般。所以,讀這些稱呼時我們要讀得輕柔深情些?!驹O計意圖】這一環(huán)節(jié)不僅能展示學生的閱讀成果,還能使學生感受到閱讀的成就感,并在相互交流中產(chǎn)生更深刻的理解和感悟,在朗讀和評價中體會父愛。二、感悟成長1.解讀“虎爸”師:在同學們的閱讀分享中,傅雷這樣一個深愛兒子的父親形象深入人心。其實,傅雷早期對傅聰?shù)慕逃呛車揽恋模且粋€“虎爸”的形象。我們一起來看一則小故事。

4.教學比例的各部分名稱這部分的教學,我采用了閱讀自學法。實施素質(zhì)教育,使學生由“學會”變“會學”,這里我注重培養(yǎng)學生的自學能力,師生的雙邊關系亦實現(xiàn)從扶到放的轉(zhuǎn)變。在學生自學課本時,老師寫出比例的兩種形式,引導學生注意內(nèi)項和外項的位置。5.教學比例的基本性質(zhì)觀察80:2=200:5中的兩個內(nèi)項的積與兩個外項的積的關系,引導學生把兩個外項與兩個內(nèi)項分別相乘,比較結果,然后引導他們回答:2:3 = 0.4:0.6。兩個內(nèi)項的積與兩個外項的積有什么關系?再讓學生歸納出比例的基本性質(zhì),探討寫分數(shù)形式,歸納“交叉相乘”積相等。小結:比例的基本性質(zhì)可以檢驗組成的比例對不對?并提問:4:9=5:10成立嗎?比例的基本性質(zhì)是本課的第二個重點。為了突出重點,我引導學生通過計算幾個比例式的內(nèi)項積和外項積,也從特殊到一般的推理方式,引導學生發(fā)現(xiàn)規(guī)律,總結概括性質(zhì)。同時也滲透了實踐第一的觀點。

(3)分別在射線OA,OB,OC,OD上取點A′、B′、C′、D′,使得 ;(4)順次連接A ′B′、B′C′、C′D′、D′A′,得到所要畫的四邊形A′B′C′D′,如圖2.問:此題目還可以 如何畫出圖形?作法二 :(1)在四邊形ABCD外任取一點 O;(2)過點O分別作射線OA, OB, OC,OD;(3)分別在射線OA, OB, OC, OD的反向延長線上取點A′、B′、C′、D′,使得 ;(4)順次連接A ′B′、B′ C′、C′D′、D′A′,得到所 要畫的四邊形A′B′C′D′,如圖3. 作法三:(1)在四邊形ABCD內(nèi)任取一點O;(2)過點O分別作 射線OA,OB,OC,OD;(3)分別在射線OA,OB,OC,OD上取點A′、B′、C′、D′,使得 ;(4)順次連接A′B′、B′C ′、C′D′、D′A′,得到所要畫的四邊形A′B′C′D′,如圖4.(當點O在四邊形ABCD的一條邊上或在四邊形ABCD的一個頂點上時,作法略——可以讓學生自己完成)三、課堂練習 活動3 教材習題小結:談談你這節(jié)課學習的收獲.

①分別連接OA,OB,OC,OD,OE;②分別在AO,BO,CO,DO,OE上截取OA′,OB′,OC′,OD′,OE′,使OA′OA=OB′OB=OC′OC=OD′OD=OE′OE=13;③順次連接A′B′,B′C′,C′D′,D′E′,E′A′.五邊形A′B′C′D′E′就是所求作的五邊形;(3)畫法如下:①分別連接AO,BO,CO,DO,EO,F(xiàn)O并延長;②分別在AO,BO,CO,DO,EO,F(xiàn)O的延長線上截取OA′,OB′,OC′,OD′,OE′,OF′,使OA′OA=OB′OB=OC′OC=OD′OD=OE′OE=OF′OF=12;③順次連接A′B′,B′C′,C′D′,D′E′,E′F′,F(xiàn)′A′.六邊形A′B′C′D′E′F′就是所求作的六邊形.方法總結:(1)畫位似圖形時,要注意相似比,即分清楚是已知原圖與新圖的相似比,還是新圖與原圖的相似比.(2)畫位似圖形的關鍵是畫出圖形中頂點的對應點.畫圖的方法大致有兩種:一是每對對應點都在位似中心的同側;二是每對對應點都在位似中心的兩側.(3)若沒有指定位似中心的位置,則畫圖時位似中心的取法有多種,對畫圖而言,以多邊形的一個頂點為位似中心時,畫圖最簡便.三、板書設計

師:這是一種較為簡便、應用廣泛的方法,但有時候也要具體問題具體分析,做題時要合理靈活地選擇計算方法?!堆芯繉W生如何學比研究教師如何教更重要。學生對新知識的學習必須以已有的知識和學習經(jīng)驗作為基礎,因此正確分析學生的知識基礎和學習經(jīng)驗就顯得格外重要。我認為分數(shù)除以整數(shù)的教學基礎在于以下幾點:分數(shù)與小數(shù)的轉(zhuǎn)化;分數(shù)的意義;分數(shù)乘法的意義;倒數(shù)的知識;商不變的性質(zhì)等。這些知識在以前的學習中,學都有了足夠的掌握。有了上面的分析基礎,我覺得把研究新知識的權力教給學生,是完全可以的?!?、質(zhì)疑與反思。師:對于這些方法,盡管大家的思維角度不盡相同,但是基本的想法是相同的,想一想我們是怎樣解決問題的?生:用學過的倒數(shù)、商不變的性質(zhì)解決的。師:對。用一句話概括就是運用舊知識解決新新問題。這是一種很重要的學習方法。5、實踐體驗練習鞏固。

一.說教材。我說課的內(nèi)容是人教版課程標準實驗教科書六年級上冊的分數(shù)除法單元中的例1和例2。例1是分數(shù)除法的意義認識,例2是分數(shù)除以整數(shù)的計算。在這之前學生已經(jīng)掌握了整數(shù)除法的意義和分數(shù)乘法的意義及計算,而本課的學習將為統(tǒng)一分數(shù)除法計算法則打下基礎。例1先是整數(shù)除法回顧,再由100克=1/10千克,從而引出分數(shù)除法算式,通過類比使學生認識到分數(shù)除法的意義與整數(shù)除法的意義相同,都是‘已知兩個因數(shù)的積和其中一個因數(shù),求另一個因數(shù)的運算’。例2是分數(shù)除以整數(shù)的計算教學,意在通過讓學生進行折紙實驗、驗證,引導學生將‘圖’和‘式’進行對照分析,從而發(fā)現(xiàn)算法,感悟算理,同時也初步感受數(shù)形結合的思想方法。根據(jù)剛才對教材的理解,本節(jié)課的教學目標是:1、理解分數(shù)除法的意義與整數(shù)除法的意義相同。2.理解分數(shù)除以整數(shù)的計算原理,掌握計算方法,并能正確的進行計算。

一、課前準備師:同學們想一想,你同父母一起去商店買衣服時,衣服上的號碼都有哪些,標志是什么?學生:我看到有些衣服上標有M、S、L、XL、XXL等號碼.但我不清楚代表的具體范圍,適合什么人穿,但肯定與身高、胖瘦有關.師:這位同學很善動腦,也愛觀察.S代表最小號,身高在150~155cm的人適合穿S號.M號適合身高在155~160cm的人著裝……廠家做衣服訂尺寸也并不是按所有人的尺寸定做,而是按某個范圍分組批量生產(chǎn).你覺得這種生產(chǎn)方法有什么優(yōu)點?學校要為同學們訂制校服,為此小明調(diào)查了他們班50名同學的身高,結果(單位cm).如下

1. We'll need ten months at least to have the restaurant decorated.2.Some traditional Chinese dishes from before the Ming Dynasty are still popular today.3.My grandpa's breakfast mainly includes whole grain biscuits and a glass of milk.4.People in this area would eat nearly a kilo of cheese per week.5. We enjoyed a special dinner in a fancy restaurant where the waiters all wore attractive suits.6. He prefers this brand of coffee which, as he said, has an unusually good flavor.Key:1. at a minimum 2. prior to3. consist of4. consume5. elegant6. exceptionalStep 5:Familiarize yourself with some food idioms by matching the meaning on the right with the colored words on the left.1.Public concern for the health of farm animals has mushroomed in the UK2.Anderson may be young but he's certainly rolling to doing dough!3.George is a popular lecturer. He often peppers his speech with jokes.4.As the person to bring home the bacon, he needs to find a stable job.5 He is often regarded as a ham actor for his over emphasized facial expressions. The media reported that these companies had treated pollution as a hot potato. 6.The media reported that these companies had treated pollution as a hot potato.7.Don't worry about the test tomorrow. It's going to be a piece of cake!8. It's best to fold the swimming ring when it is as flat as a pancake.A. completely flatB. something that is very easy to do C.an issue that is hard to deal withD.to include large numbers of somethingE.to earn on e's living to support a familyF. wealthyG.to rapidly increase in numberH. an actor who performs badly, especially by over emphasizing emotions

The activity theme of this section is to design various activities around the key words in the first text. Therefore, the activities require students to pay attention to the spelling of words. On the other hand, let students grasp the meaning of words more accurately through sentences and short texts. This kind of teaching design also helps to improve the ability of using English thinking.1. Cultivating students' ability to use word formation to induce and memorize vocabulary, and the ability to use lexical chunks to express meaning.2. Guide the students to think independently and use the correct form of words to complete sentences3. Cultivate students' habit of using lexical chunks to express language completely, guide students to draw words in sentences quickly, pay attention to word collocation, so as to accumulate more authentic expressions4. Instruct students to create sentences with the chunks.1. Enable students to use the language points in the real situation or specific contexts flexibly and appropriately.2. Guiding the Ss to use unit topic words and the sentence patterns in a richer context.Step1: Think of a word that best fits each definition.1. to remember sth2.to accept, admit, or recognize sth or the truth/existence of sth3. the process of changing sth or yourself to suit a new situation4 .to make sb feel less worried or unhappy5. a strong desire to achieve sth

The theme of this section is to express people's views on studying abroad. With the continuous development of Chinese economic construction, especially the general improvement of people's living standards, the number of Chinese students studying abroad at their own expense is on the rise. Many students and parents turn their attention to the world and regard studying abroad as an effective way to improve their quality, broaden their horizons and master the world's advanced scientific knowledge, which is very important for the fever of going abroad. Studying abroad is also an important decision made by a family for their children. Therefore, it is of great social significance to discuss this issue. The theme of this section is the column discussion in the newspaper: the advantages and disadvantages of studying abroad. The discourse is about two parents' contribution letters on this issue. They respectively express their own positions. One thinks that the disadvantages outweigh the advantages, and the other thinks that the advantages outweigh the disadvantages. The two parents' arguments are well founded and logical. It is worth noting that the two authors do not express their views on studying abroad from an individual point of view, but from a national or even global point of view. These two articles have the characteristics of both letters and argumentative essays1.Guide the students to read these two articles, and understand the author's point of view and argument ideas2.Help the students to summarize the structure and writing methods of argumentative writing, and guides students to correctly understand the advantages and disadvantages of studying abroad3.Cultivate students' ability to analyze problems objectively, comprehensively and deeply

? B: Absolutely! Getting involved with Chinese cultural activities there definitely helped a lot. I got to practice my Chinese on a daily basis, and I could learn how native Chinese speakers spoke.? A: What do you feel is your biggest achievement?? B: Learning Chinese characters! I have learnt about 1,500 so far. When I first started, I didn't think it was even going to be possible to learn so many, but now I find that I can read signs, menus, and even some easy newspaper articles.? A: What are you most keen on?? B: I've really become keen on learning more about the Chinese culture, in particular Chinese calligraphy. As I have learnt Chinese characters, I have developed a great appreciation for their meaning. I want to explore Chinese characters by learning how to write them in a more beautiful way. ? A: Finally, what do you want to say to anyone interested in learning Chinese?? I have really become keen on learning more about the Chinese culture, in particular Chinese Calligraphy. As I have learnt Chinese character, I have developed a great appreciation for their meaning. I want to explore Chinese characters by learning how to write them in a more beautiful way.? A: Finally, what do you want to say to anyone interested in learning Chinese?? B: I'd say, give it a shot! While some aspects may be difficult, it is quite rewarding and you will be happy that you tried.? A: Thanks for your time. ? B:You're welcome.

This section guides students to pay attention to the typical context of vocabulary use, helps students accumulate vocabulary around the key vocabulary of this unit, and uses the learned words and word chunks in different contexts to deeply understand their meaning and usage, so as to achieve the purpose of review and consolidation.The teaching design activities aim to guide students to pay attention to the typical context in which the target vocabulary is used, as well as the common vocabulary used in collocation, so that students can complete the sentence with correct words. In terms of vocabulary learning strategies, this unit focuses on cultivating students' ability to pay attention to collocation of words and to use word blocks to express meaning.For vocabulary learning, it is not enough just to know the meaning of a single word, but the most important thing is to master the common collocations of words, namely word blocks.Teachers should timely guide students to summarize common vocabulary collocation, such as verb and noun collocation, verb and preposition collocation, preposition and noun collocation, and so on.1. Guide students to understand and consolidate the meaning and usage of the vocabulary in the context, 2. Guide the students to use the unit topic vocabulary in a richer context3. Let the students sort out and accumulate the accumulated vocabulary, establishes the semantic connection between the vocabulary,4. Enable students to understand and master the vocabulary more effectivelyGuiding the Ss to use unit topic words and the sentence patterns in a richer context.

The purpose of this section of vocabulary exercises is to consolidate the key words in the first part of the reading text, let the students write the words according to the English definition, and focus on the detection of the meaning and spelling of the new words. The teaching design includes use English definition to explain words, which is conducive to improving students' interest in vocabulary learning, cultivating their sense of English language and thinking in English, and making students willing to use this method to better grasp the meaning of words, expand their vocabulary, and improve their ability of vocabulary application. Besides, the design offers more context including sentences and short passage for students to practice words flexibly.1. Guide students to understand and consolidate the meaning and usage of the vocabulary in the context, 2. Guide the students to use the unit topic vocabulary in a richer context3. Let the students sort out and accumulate the accumulated vocabulary, establishes the semantic connection between the vocabulary,4. Enable students to understand and master the vocabulary more effectivelyGuiding the Ss to use unit topic words and the sentence patterns in a richer context.Step1: Read the passage about chemical burns and fill in the blanks with the correct forms of the words in the box.

The theme of this activity is to learn the first aid knowledge of burns. Burns is common in life, but there are some misunderstandings in manual treatment. This activity provides students with correct first aid methods, so as not to take them for granted in an emergency. This section guides students to analyze the causes of scald and help students avoid such things. From the perspective of text structure and collaborative features, the text is expository. Expository, with explanation as the main way of expression, transmits knowledge and information to readers by analyzing concepts and elaborating examples. This text arranges the information in logical order, clearly presents three parts of the content through the subtitle, accurately describes the causes, types, characteristics and first aid measures of burns, and some paragraphs use topic sentences to summarize the main idea, and the level is very clear.1. Guide students to understand the causes, types, characteristics and first aid methods of burns, through reading2. Enhance students’ ability to deal withburnss and their awareness of burns prevention3. Enable students to improve the ability to judge the types of texts accurately and to master the characteristics and writing techniques of expository texts.Guide students to understand the causes, types, characteristics and first aid methods of burns, through readingStep1: Lead in by discussing the related topic:1. What first-aid techniques do you know of ?CPR; mouth to mouth artificial respiration; the Heimlich Manoeuvre
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