一、教材分析行星的運動選自人教版普通高中物理必修2第六章第1節(jié)。本節(jié)教學既是前面《運動的描述》和《曲線運動》內(nèi)容的進一步的延伸和拓展,又能為后面學習萬有引力定律做鋪墊。在本章中占有較為重要的地位,具有承前啟后的作用。同時該節(jié)內(nèi)容也涉及大量物理史實、貼近學生生活和聯(lián)系社會實際的事實,可進一步培育學生的科學情感、精神和發(fā)展觀。(一)教學目標 1.知識與技能(1)知道地心說和日心說的基本內(nèi)容。(2.)掌握理解開普勒三大定律的內(nèi)容,并能應用。(3)理解人們對行星運動的認識過程是漫長復雜的,真理是來之不易的。2.過程與方法通過托勒密、哥白尼、第谷·布拉赫、開普勒等幾位科學家對行星運動的不同認識,了解人類認識事物本質(zhì)的曲折性并加深對行星運動的理解。3.情感、態(tài)度與價值觀(1)澄清對天體運動神秘、模糊的認識,掌握人類認識自然規(guī)律的科學方法。(2)感悟科學是人類進步不竭的動力。
Textbook: Senior English for China (Book 4), by Liu Daoyi Time Allotment: 1 period (40 minutes)Date: March 20, 2014Teaching aids: blackboard, Multi-media, Power Point, chalk I. Text Analysis (教材分析)This unit is about body language, and the text selected in the reading part demonstrates the difference and similarity of body language in many parts of the world. Through learning this passage, students are required to raise their awareness of using body language in different parts of the world. As body language is closely related to our daily life, it is easy to arouse students’ interest in learning this text. Reading skills and speaking training are designed around the text.II. Teaching Objectives (教學目標)By the end of the lesson, students will be able to:1. Language Skill Objective(語言技能目標): develop reading ability (skimming and scanning)as well as speaking ability.2. Cultural Knowledge Objective(文化知識目標): know about the cultural differences of using body language.3. Affective Objective(情感目標): increase students’ awareness of using body language correctly in different cultures. III.Teaching Focuses and Difficulties(教學重點和難點)1. Teaching Focuses(教學重點): the difference and similarity of body language in many parts of the world.2. Teaching Difficulties(教學難點): develop students’ reading abilities of skimming and scanning and ask the students to show their opinions with fluent English.
Good morning, distinguished judges:It’s my honor to talk about my teaching ideas with you. Today my topic is Women of Achievement. My presentation consists of six parts: the analysis of teaching material and student, teaching aims, key and difficult points, teaching and studying method, teaching procedures and blackboard design.First, let’s focus on the analysis of teaching material. This lesson is from New Senior English for China Student’s Book 4 Unit 1, the reading part. The main topic of the passage is the introduction of a student of Africanwildlife. After this lesson, the students will learn more information about her studying chimps in Africa, and their reading and speaking abilities can be developed as well.The next part is the analysis of students. My students are in senior high students. They have learnt English for many years, they’ve known many words and sentences, but their speaking and reading abilities are still not very good. So I will practice their speaking and reading abilities through different exercises.According to the New Standard Curriculum and the present situation, I set the teaching aims as follows: firstly, knowledge aims. Students can grasp some new words, such as worthwhile, move off. Moreover, students can understand the content of the passage and get familiar with the topic of studying chimps in wildlife. Secondly, ability aims. Students can use reading strategies such as skimming and scanning in reading process. Thirdly, emotional aims. Students can have the awareness of protecting animals and care about animals.Based on the above analysis, the key point of this lesson is to get the main idea and the detailed information from the passage; the difficult point is to talk about the wildlife protection and use reading strategies.
Then I would ask them to think of a funny English or Chinese and tell it to partners. While telling stories, they can use expressions and some acting to help make the story funny. 5 minutes would be given to do this.Those stories they told there will be the material for their writing. Soletting them tell it at first is helpful. And they can make a difference between telling a funny story and writing it down. Generally speaking, it is difficult forstudents to write well because they don’t know what to write and how to write. Asking them to tell their own stories at first can help them come up with what to write.After their telling, I would invite someone to share his/her story with all of us and I would write it down on the blackboard.This example story would be used as a sample to illustrate the format of funny story. Different from a story from teacher or textbook, a story from students can obviously become a interesting material to draw students’ attention.Then I would ask the whole class to put this story into several parts. It might be a little bit difficult for them. So I would ask them to find out whether all the sentences are necessary. After delete some sentences, there are 6 sentences left behind. Then they can easily put them into three parts. After interaction with students, I would teach them the right terms for each part and conclude the format of funny story.This step is the key and difficult point in my lesson. So I mainly usetask-based teaching method in this part and the task for students was divided into several stages. With the separated difficult level, students can find there are usually three parts in writing. They can also learn to write without the unnecessary parts in the process of analyzing. And then I wouldn’t rush to tell them the right terms to them directly. Instead, I would ask them to name them by their own. A confused mind is better for acquiring knowledge.While-writing:Then I would give students 7 minutes to write down this story, without other requirements.With all the preparations in pre-writing, students’ difficulties were cleared. So it would be much easier for them to write down the story within 7 minutes. There are no other requirements because students’ first writing is actually a drafting. It would be revise and edit several times later. Writing, as a skill
Good afternoon, teachers, It’s my great pleasure to be here sharing my lesson with you.The content of my lesson is Senior English Book 3 Unit 5 Canada —— “The true North”.I’ll be ready to begin this lesson from five parts. Analysis of the teaching material,the teaching methods,the studying methods, the teaching procedure,and Blackboard design.First, let me talk about the teaching material.Part 1 Teaching Material:This unit is about the introduction of Canada. By studying of this unit,we’ll enable the students to learn the geography, population, main cities, and natural beauty, natural resources of Canada. Through the training of the unit, it also requires students to learn some Language skills such as the expressions of position and emotions.So it plays an important part in the English teaching in this book.After studying the teaching material and analyzing the rule of children’s growing of mind,I think the teaching aims are the followings:1.Knowledge objects:(1) make the students learn some new words and phrases(2) make the students understand the content of the lesson.2.Ability objects:(1)To develop the Ss’ abilities of listening, speaking, reading and writing. Especially reading and speaking ability.(2) learn to talk about the characters of Canada in English(3)To train the Ss’ ability of working in pairs.3.Emotion objects:(1)Enable students to understand the characters of Canada..(2)Stimulate Ss to work hard to make China stronger.Part 2 Teaching Methods:I think helping students learn to master new words and phrases and improve the students’ reading and speaking ability is import and the difficult.According to the analysis of the teaching material and the import points and the difficult points,I will use the following teaching methods : question-guiding approach; fast-reading and careful reading; multi-media teaching methods; discussion
The oldest and the most popular park in the worldenjoy the exciting activities thereget close to the life-size cartoon characters like Mickey Mouse and Donald Duck Step 3 Pre-reading1.What do you suppose a theme park is ?2.What do you think you can see in a theme park?(1.It is a kind of amusement park which has a certain theme – that the whole park is based on. 2.buildings, castles, statues, rare animals and birds, and so on.) Step 4 Reading ----- Theme Parks –---- Fun and More Than Fun1.Predict : Read the title and the pictures on P. 34 and PredictWhat is the meaning of the title “Theme Park – Fun and more than fun”?(The title means that theme parks are fun to visit, but that they can also be educational and can offer useful information.)2.Skimming Fast read and answer:What activities can we take in a theme park?Amusement park: Bumper car Merry-go-round slide bungee jumping Free-fall rides Horror films Pirate ship Ferris wheel roller coaster3.Scanning Read again and you will find various theme parks are mentioned in the passage . Then what are they ?Theme parks: Sports theme park History theme park Culture theme park Marine or Ocean theme Park Future park Science theme park Disneyland4.Careful reading and find the main idea of each paragraph:THEME PARKS---- entertaining/ educationalPara.1 Traditional parks are places to go for relaxation and to have time away from our busy lives.Para.2 Theme parks are different They’re large and full of things to do, see and buy.Para.3 Theme parks are built around a single idea or theme. One example is a sports park.Para.4 Another kind of theme park is historical more and cultural and can be educational.Para.5 Disneylandwas the first theme park. It is based on the fantasy life and characters of Disney’s films.Para.6 Some examples of educational theme parks include sea world parks and science parks.
Language learning needs a context, which can help the learners to understand the language and then can product comprehensible output, so computer has the advantages to make the materials attractive.Part 3 Learning MethodsTask-based, self-dependent and cooperative learningPart 4 Teaching ProcedureStep One Lead-in“Interest is the best teacher.” Therefore, at the very beginning of the class, I should spark the students’ mind to focus on the centre topic “the band”. I’ll show some pictures of food to attract their attention and then bring some questions.Question:What kind of food they like?What should go into a good meal?The answers must relate to the diet. After this, the students will be eager to know something about a balance diet and this is the very time to naturally lead the class into Step 2Step 2 Reading for information: skimming and scanning In this step, I use Task-based Language Teaching method, which can give students a clear and specific purpose while skimming and scanning the context.Task 1 General ideaThe students will be asked to just glance at the title and the pictures of the passage, and then guess what they will read in the text. And they’ll be divided into groups of four to have a discussion.The purpose is to inspire the students to read actively, not passively. In addition, the task is to develop the students’ reading skill by making prediction and to encourage the students to express their thoughts in English and cooperate with each other.Task 2 Main idea of each paragraphCooperative learning can raise the students’ interest and create an atmosphere of achievement. Based on this theory, I divide the whole class into 4 groups to skim the whole text and get the main idea of each paragraph.
Knowledge objectives:(1) to make Ss grasp the usage of words, expressions and sentence structures: statistics, struggle, thanks to, rid of, some patterns for persuasion, the “ing” form as subject and object;(2)to use learnt knowledge to persuade sb.Ability objectives:(1) to develop Ss’ reading skills(skimming, scanning, word guessing);(2) to improve Ss’ speaking, communicating and cooperating skills.Emotional objectives:to make Ss know the contribution of Yuan,and learn his spirit and his simple life time.Teaching important and difficult points:(1) some words, expressions and sentence structures mentioned above;(2)the content of the text;(3)training their reading and speaking skills.Teaching methods: CLT, TBLT,QT.Learning strategies: CLS, QLS, TBLS.Teaching procedures:Step 1 lead-in: (1) teacher plays a piece of recent news from CCTV about the harvest of the super hybrid rice, and ask students whether they know Yuan or not, and talk about him and his contribution.(2)Brain storm: let Ss describe Yuan in their minds including his appearance, his living condition and so on.Step 2 fast reading tasks:(1)teacher introduces Yuan and super hybrid rice(2)make Ss read the text as fast as possible with questions. Such as: what’s the general ideaof this passage? What’s Yuan’ dream? (skimming and scanning skill)Step 3 intensive reading tasks(1)let Ss read the text silently, find topic sentence of each paragraph and draw the difficult sentences and the knowledge what they don’t understand.(words guessing)(2)teacher and Ss talk about the important words, expressions and sentences together, and ask Ss to retell the content of the text.(summarizing and paraphrasing)(3)teacher summarize this part.(4) read again following the courseware.
今天我們來介紹一下必修五第四單元的授課方式。這個單元的題目是Making the news。應該是學生比較感興趣的話題,學生往往對新聞工作充滿好奇,所以我們可以利用這個機會多設計一些師生互動和學生互動,來激發(fā)起學習的積極性,提高學習效率。同時我們可以利用這個單元不僅幫助學生掌握語言知識,培養(yǎng)語言能力,同時讓其了解新聞工作的重要性,培養(yǎng)起社會智能感。這個單元分為六個課時,它的教學目標是這樣的:語言目標是掌握詞匯表中的常用單詞和短語,掌握倒裝句的一些基本用法。 技能目標是能初步掌握約會的基本句型并在真實的場景下正確運用。新聞報道類文章的寫作技能。采訪的基本規(guī)范和溝通技能。情感目標是對新聞報道的客觀性和真實性有更好的理解。對新聞記者的職業(yè)有更深入的了解,并能體會其工作的重要性。下面我們來介紹一下第一課時的授課方式,第一課的教學目標是這樣的第一課時的教學目標語言目標:單詞:Occupation, journalist, editor, photographer, curious, personality, enthusiasm
通過寫文章梗概,培養(yǎng)學生綜合運用語言的能力,學習用恰當?shù)挠⒄Z描述科學家的故事。這是本課的教學難點。教師可以使用完形填空的方式來幫助學生整理語篇,從而來降低難度。本課的教學重點的突破方法是:在閱讀前,讓學生初步了解得出科學觀點所需要的基本程序,從而輕松而自然地導入文章的閱讀;在閱讀過程中,由易到難設計快速閱讀和精讀的問題,層層推進各種閱讀活動,讓學生對閱讀內(nèi)容從整體感知到細節(jié)理解,最后深層讀懂整篇文章,同時加強閱讀策略的指導,讓每個學生都主動參與課堂教學活動,最終達到提高閱讀能力的目的。Step 4 Post-readingGroup Activities四人小組共同合作,在老師的適當指導下,就以下2個問題展開討論,讓學生就所知、所學、所感和所想融入話題,然后抽若干同學代表作小組發(fā)言。1. What do you think about John Snow, and what should we learn from him?2. Cholera was 19th century disease, which two diseases are similar to cholera today? Why?
Teaching Aims:Knowledge 1. Get the students to learn the useful new words and expressions in this section. Aims:2. Let the students learn about how the UK was formed and the four groups of invaders.1. Develop students’ reading ability and let them learn different Ability reading skills. Aims:2. Enable students to learn to talk about the United Kingdom and the Union Jack Emotional 1. Let students know more about the UK2. Develop students’ sense of cooperative learning Aims:Teaching Important Points:1. Let the students learn about the countries of the United Kingdom and the Union Jack2. Get the students to read the passage and know about how the UK was formed and the four groups of invaders.3. Have the students learn different reading skills.Teaching Difficult Ponts:1. Develop students’ reading ability.2. Enable students to talk about the United Kingdom and the Union Jack.3. Let students learn how the UK was formed geographically and historically.Teaching Methods:Showing pictures, asking, exercising, listening, reading etc.Teaching Aids:A computer,a projector and a blackboard.Teaching Procedures: 1) Show a map of the world, ask students the following questions:Where is the UK?What’s the full name of the UK?2) Ask the students work in pairs to do the quiz on Page 9.Do you want to test how many things you know about the United Kingdom? Let’s have a small test.Using the map on P9, students answer the following questions:?How many countries does the UK consist of? What are they??England is divided into three main areas. Do you know what they are? 1) Scanning (10Minutes )Let the students hold the questions asked in pre-reading and read the passagequickly and then let them do the following exercise.Join lines to the right answer.
一、人類遺傳病1.概念2.分類(1)單基因遺傳病(2)多基因遺傳病(3)染色體異常遺傳?、僭颌陬愋?遺傳病的特點4.遺傳病對人類的危害八、說布置作業(yè)在作業(yè)的布置中,我嚴格遵循“重質(zhì)量、輕負擔”的指導思想。第一題主要是為了幫助學生及時糾正原有的對知識的錯誤理解或片面認識,培養(yǎng)學生的解題技巧和技能。所以我選用了該題。同時想借助該題培養(yǎng)學生對問題的科學的思維方法和探究的精神。幫助學生提高對信息技術運用的熟練程度,發(fā)展學生的信息素養(yǎng)。附作業(yè):1、連線題,請同學們連線指出下列遺傳各屬于何種類型?(1)苯丙酮尿病 A、單基因遺傳病(2)21三體綜合征(3)抗維生素D佝僂病 B、多基因遺傳?。?)軟骨發(fā)育不全(5)青少年型糖尿病 C、常染色體病2、以生物小組為單位進行人類遺傳病的調(diào)查。
一、導入新課人類社會越來越現(xiàn)代化,新科學技術日新月異,令人目不暇接,稱之到了“知識爆炸”的時代也毫不為過。由此而來的是生活的快節(jié)奏,學習和工作的競爭也越來越激烈。這種競爭一直波及到了兒童,加之中國幾千年來形成的望子成龍的傳統(tǒng)觀念,使作父母的把一切希望都寄托在孩子身上,實現(xiàn)自己未能實現(xiàn)的理想。祖孫三代4、2、1的局面,使12只眼睛都盯在了孩子身上,真是走路怕摔著,吃飯怕噎著,干活怕累著,要星星不敢摘月亮,要吃什么跑遍全城也要買來。這種過分保護、溺愛及過早地灌輸知識會得到什么結(jié)果呢?樂觀者說孩子越來越聰明,越來越早熟,將來能更好適應現(xiàn)代化的要求;悲觀者則認為豆芽菜式的孩子將來經(jīng)不起風浪,小皇帝太多了很難凝聚成統(tǒng)一力量,將來誰去當兵,誰去干那些艱苦創(chuàng)業(yè)性工作……。對孩子本身來說,是幸福還是……在此不想多發(fā)議論,還是讓我們來看看動物世界的孩子們吧,也許會得到某種啟迪。
f.有絲分裂的意義(討論分析教學),首先引導學生結(jié)合所學知識討論有絲分裂的的作用,最后有教師歸納總結(jié),并要求學生在理解的基礎上記憶。g.無絲分裂(圖形直觀教學、簡介),本部分內(nèi)容不是教學的重點,內(nèi)容也相對簡單,所以我的教學方法是直接給學生展示掛圖,再進行簡短介紹,讓學生了解即可。h.引出減數(shù)分裂的概念,為第五章學習打下基礎。小結(jié):新課講完以后由教師對本節(jié)內(nèi)容進行總結(jié)鞏固和反饋:進行一些課堂練習達到鞏固和反饋的作用。最后布置作業(yè),各種難度的作業(yè)題目均設置一些,其中簡單題比重大,難題要求學生選作,這樣提高學生學習積極性。2教學媒體程序設計: 細胞周期的概念(多媒體課件演示周期動畫)植物細胞有絲分裂(多媒體課件演示分裂各期動畫)動植物細胞有絲分裂異同點(多媒體課件演示分裂各期動畫)有絲分裂過程中DNA和染色體數(shù)量的變化規(guī)律(掛圖演示,包括表格和函數(shù)圖象)
(1觀察圖解,色盲基因在性別間是如何傳遞的呢?(女--女、女--男、男--女)(2)為什么不能由男性傳給男性?(色盲基因是在X染色體上,因此色盲基因是隨X染色體的傳遞而傳遞。)(3)男性的色盲基因怎樣才能傳給男性呢?(通過女兒,傳給外孫即交叉遺傳)(4)從圖解看色盲在男女中的發(fā)病情況怎樣?(男性多于女性)(5)從社會調(diào)查也是這樣,你是否能從基因和染色體的角度加以解釋?(提示:女性染色體的構成,結(jié)合基因位置及顯隱性進行分析)歸納特點:歸納出色盲基因遺傳的特點并擴展到X染色體隱性遺傳的特點上。色盲基因遺傳(X隱性遺傳)的特點:(1)男患者多于女患者(2)交叉遺傳(3)女病兒子必病,男正女兒必正等。問題探討:利用“遺傳圖解”結(jié)合“問題鏈”繼續(xù)探討,拓展到抗維生素D即X 染色體顯性遺傳的特點。(6)色盲基因在X染色體上屬隱性基因,子代表現(xiàn)男多于女,對應的正常色覺基因則屬于X顯性基因,子代表現(xiàn)應如何?(女多于男)
在講述細胞分化的意義時,也可以用實例來解決,工廠的生產(chǎn)車間里不同的工人干著不同的工作,一件產(chǎn)品的產(chǎn)出需要這些工人才能創(chuàng)造出來,一個生物體就像一個車間一樣,不同的細胞各司其職,相互合作。工人的分工是主管調(diào)解出來的,而不同細胞的出現(xiàn)就是細胞分化的結(jié)果,所以說,細胞的分化是生物體發(fā)育的基礎。在講到細胞全能性的時候,要多給學生舉些關于細胞全能性的例子,如植物組織培養(yǎng)、克隆技術等等,讓學生從實際的例子中真正的悟出細胞全能性的含義。此外,還要重視教材中的疑問,適當對題目進行引申,使它的作用更加突出,有利于學生對知識的串聯(lián)、積累、加工,從而達到舉一反三的效果。怎樣來解釋細胞的全能性呢?這主要以講授法來解釋了,細胞全能性的體現(xiàn)需要在組織或器官離體后才能體現(xiàn)出來,每個細胞都包含著生物體的全套遺傳基因,通過基因選擇性的表達,使離體的組織或器官通過分裂和分化逐漸發(fā)育成完整的植株。
三、孟德爾遺傳規(guī)律的現(xiàn)代解釋①分離定律:在雜合體的細胞中,位于一對同源染色體上的等位基因,具有一定的獨立性;在減數(shù)分裂形成配子的過程中,等位基因隨同源染色體的分開而分離,獨立地隨配子遺傳給后代。②自由組合定律:位于非同源染色體上的非等位基因的分離或組合是互不干擾的;在減數(shù)分裂過程中,同源染色體的等位基因彼此分離的同時,非同源染色體上的非等位基因自由組合??偨Y(jié):再次強調(diào)孟德爾遺傳定律的現(xiàn)代解釋課堂練習:書本31頁6、教學反思:本節(jié)課設置了一系列問題情境,層層設問,在學生答問、質(zhì)疑、討論過程中讓學生建構新概念和新的知識體系,并通過教師及時掌握反饋信息,適時點撥、調(diào)節(jié),讓學生在推理判斷中培養(yǎng)良好的思維習慣和對知識的遷移能力,而且通過留出一定的時間讓學生提問,體現(xiàn)了以學生為主體的思想。
四、說教學程序(一).溫故知新、導入新課復習提問:基因突變導致生物變異的原因是什么?回答:基因突變是基因結(jié)構發(fā)生改變,從而使遺傳信息改變,使蛋白質(zhì)結(jié)構改變、生物性狀改變,即生物發(fā)生了變異。那么,基因是什么?它和染色體又有何關系?回答:基因是有遺傳效應的DNA片斷,染色體是DNA的載體,基因在染色體上呈線形排列。引出新知:對于一個生物體來說,正常情況下,其染色體的結(jié)構和數(shù)量都是穩(wěn)定的。但在自然條件或人為因素的影響下,染色體的結(jié)構和數(shù)量均會發(fā)生改變,從而導致生物性狀的改變,這就屬于染色體變異。(二).把握重點、突破難點重點的把握:1、染色體結(jié)構的變異播放影片:貓叫綜合征幼兒。讓學生觀察: 患兒哭聲輕、音調(diào)高,很像貓叫。教師補充: 患兒的征狀---兩眼較低、耳位低下,存在著嚴重的智力障礙。闡述病因---染色體片段缺失
一、說教材《開辟新航路》是高中《歷史·必修二》第5課的內(nèi)容。從三個方面向?qū)W生介紹了歐洲人開辟新航路的歷史:即新航路開辟的原因和條件、新航路開辟經(jīng)過以及影響。前4課內(nèi)容介紹了古代中國經(jīng)濟的基本結(jié)構與特點,從第5課開始學習資本主義世界市場的形成和發(fā)展。本課內(nèi)容相當重要,上承古代中國,下啟近代世界。新航路的開辟,打破了世界相對隔絕的狀態(tài),世界真正開始融合為一個整體。從此,以西歐為中心的世界市場的雛形開始出現(xiàn)。隨后的殖民擴張,世界市場拓展;第一次工業(yè)革命,世界市場基本形成;第二次工業(yè)革命,世界市場發(fā)展。二、說目標1、課程標準概述迪亞士、哥倫布開辟新航路的史實,認識地理大發(fā)現(xiàn)對世界市場形成的意義。2、三維目標①知識與能力:掌握新航路開辟的原因、經(jīng)過、影響。②過程與方法:引導學生分析原因及影響,培養(yǎng)學生分析和歸納問題的能力。③情感態(tài)度與價值觀:A、通過對新航路開辟過程的學習,使學生感受和學習探險家們勇于進取的開拓精神。B、通過學習新航路開辟的影響,使學生認識新航路開辟促進了人類社會的整體發(fā)展。
生2:頷聯(lián)的意思是只聽到禁衛(wèi)軍中傳來夜間巡邏的梆子聲,不再向?qū)m中那樣安逸地聽到有雞人打鳴報時的聲音了。生3:頸聯(lián)的意思是說事變發(fā)生那天軍隊發(fā)生嘩變停留不前,但當年唐玄宗以為自己可以和貴妃天天在一起,對天上的牽牛和織女一年一度的會見還加以嘲笑呢。生4:尾聯(lián)的含義是為什么唐玄宗當了四十五年的皇帝,還不如普通百姓夫妻恩愛,長相廝守。師:好的。請大家再齊讀一遍詩文,做到人人都能疏通詩的含義。學生再次齊讀。第三環(huán)節(jié):專項探究師:白居易曾說:“文章合為時而著,歌詩合為事而作?!边@首詩就是作者途經(jīng)馬嵬驛,詠馬嵬之變這一歷史事件而作,所以我們鑒賞的第三步,就是通過標題和詩文,弄清詩中的歷史事件。請同學們找出詩中哪些詩句描述了這一事件?