-
新人教版高中英語選修2Unit 1 Science and Scientists-Learning about Language教學設計
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
新人教版高中英語選修2Unit 1 Science and Scientists-Reading and thinking教學設計
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
新人教版高中英語選修2Unit 1 Science and Scientists-Discovering useful structures教學設計
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。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
新人教版高中英語選修2Unit 1 Science and Scientists-Using langauge教學設計
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!
新人教版高中英語選修2Unit 2 Bridging Cultures-Discovering useful structures教學設計
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.
新人教版高中英語選修2Unit 5 First Aid-Discovering useful structures教學設計
You have no excuse for not going.你沒有理由不去。He was punished for not having finished his homework.他因未完成作業(yè)而受到懲罰。2．動詞ing形式復合結構由物主代詞或人稱代詞賓格、名詞所有格或普通格加動詞ing，即“sb./sb.'s＋doing”構成。動詞ing形式的復合結構實際上是給動詞ing形式加了一個邏輯主語。動詞ing形式的復合結構有四種形式：①形容詞性物主代詞＋動詞ing②名詞所有格＋動詞ing③代詞賓格＋動詞ing④名詞＋動詞ingHer coming to help encouraged all of us.她來幫忙鼓舞了我們所有人。The baby was made awake by the door suddenly shutting.這個嬰兒被突然的關門聲吵醒了。Can you imagine him/Jack cooking at home?你能想象他/杰克在家做飯的樣子嗎？無生命名詞無論是作主語還是作賓語都不能用第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)在離開嗎？Excuse me for my not coming on time．很抱歉我沒能按時來。His father's being ill made him worried.他父親病了，他很擔心。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給我們舉辦一場演唱會。
新人教版高中英語必修1Unit 1 Teenage Life-Listening and Speaking & Listening and Talking教案
Step 2 Listening and Talking1. The teacher is advised to talk with their new students about the related topic: Boys and girls, do you know some structures to talk about future activities? Talking about future activitiesWe’ll …I plan to …There’ll be …I hope to …We’re going to …2. After their small talk, the teacher can move on by playing the listening and solve the following task.Underline the expressions in the sentences below Cao Jing and Max use to talk about the future.We’ll learn useful skills.I plan to improve my spoken English.There’ll be students from different schools.I hope to make new friends.We’ll talk about teenage life.I’ll learn to make a fire.There’ll be students from different countries at the camp.There’ll be some experts there to show us how to live in the wild.We’re going to learn about wildlife.I’m going to give a speech.I think I’m going to enjoy the activities.I think we’ll have a lot of fun.3. Work in groups. Plan a youth camp.Teacher make the Ss think of ideas for the camp. And they can use the questions below to get started. And have the Ss present their ideas for a youth camp to the class.●What kind of camp is it?●Who will be there?●What will they do?●What will they learn?
新人教版高中英語必修1Unit 2 Travelling Around-Listening and Speaking & Listening and Talking教案
【教學目標與核心素養(yǎng)】1. Instruct students to get main facts by listening and motivate them to talk about the topics about how to prepare for the trip and make reservations by listening and ultimately can make travel arrangements and reservations. 2. Develop students’ sense of cooperative learning and individual thinking capability. 3. Develop students’ different listening skills to solve different listening comprehensive problems.4. Help students to understand how to use the structures “the present continuous tense (be doing) is used to express future plans.【教學重難點】1. Teach students how to focus on key words, not on single words or grammar.2. Prompt Ss to talk about the related topics, such as how to prepare for the trip and make a travel plan.【教學過程】Step 1: Listening and SpeakingLead inThe teacher is advised to talk with their students about the places that they want to travel most both at home and abroad: boys and girls, if you have a chance to travel around the world, where will you go? After their small talk, the teacher can move on by finishing the following listening task:Before travelling, what do we need to prepare for the trip?
人教A版高中數(shù)學必修二總體集中趨勢的估計教學設計
（2）平均數(shù)受數(shù)據(jù)中的極端值（2個95）影響較大，使平均數(shù)在估計總體時可靠性降低，10天的用水量有8天都在平均值以下。故用中位數(shù)來估計每天的用水量更合適。1、樣本的數(shù)字特征：眾數(shù)、中位數(shù)和平均數(shù)；2、用樣本頻率分布直方圖估計樣本的眾數(shù)、中位數(shù)、平均數(shù)。（1）眾數(shù)規(guī)定為頻率分布直方圖中最高矩形下端的中點；（2）中位數(shù)兩邊的直方圖的面積相等；（3）頻率分布直方圖中每個小矩形的面積與小矩形底邊中點的橫坐標之積相加，就是樣本數(shù)據(jù)的估值平均數(shù)。學生回顧本節(jié)課知識點，教師補充。 讓學生掌握本節(jié)課知識點，并能夠靈活運用。
人教A版高中數(shù)學必修二總體取值規(guī)律的估計教學設計
可以通過下面的步驟計算一組n個數(shù)據(jù)的第p百分位數(shù)：第一步：按從小到大排列原始數(shù)據(jù)；第二步：計算i=n×p%；第三步：若i不是整數(shù)，而大于i的比鄰整數(shù)位j，則第p百分位數(shù)為第j項數(shù)據(jù)；若i是整數(shù)，則第p百分位數(shù)為第i項與第i+1項的平均數(shù)。我們在初中學過的中位數(shù)，相當于是第50百分位數(shù)。在實際應用中，除了中位數(shù)外，常用的分位數(shù)還有第25百分位數(shù)，第75百分位數(shù)。這三個分位數(shù)把一組由小到大排列后的數(shù)據(jù)分成四等份，因此稱為四分位數(shù)。其中第25百分位數(shù)也稱為第一四分位數(shù)或下四分位數(shù)等，第75百分位數(shù)也稱為第三四分位數(shù)或上四分位數(shù)等。另外，像第1百分位數(shù)，第5百分位數(shù)，第95百分位數(shù)，和第99百分位數(shù)在統(tǒng)計中也經(jīng)常被使用。例2、根據(jù)下列樣本數(shù)據(jù)，估計樹人中學高一年級女生第25，50，75百分位數(shù)。
人教A版高中數(shù)學必修二總體離散程度的估計教學設計
問題二：上述問題中，甲、乙的平均數(shù)、中位數(shù)、眾數(shù)相同，但二者的射擊成績存在差異，那么，如何度量這種差異呢？我們可以利用極差進行度量。根據(jù)上述數(shù)據(jù)計算得：甲的極差=10-4=6 乙的極差=9-5=4極差在一定程度上刻畫了數(shù)據(jù)的離散程度。由極差發(fā)現(xiàn)甲的成績波動范圍比乙的大。但由于極差只使用了數(shù)據(jù)中最大、最小兩個值的信息，所含的信息量很少。也就是說，極差度量出的差異誤差較大。問題三：你還能想出其他刻畫數(shù)據(jù)離散程度的辦法嗎？我們知道，如果射擊的成績很穩(wěn)定，那么大多數(shù)的射擊成績離平均成績不會太遠；相反，如果射擊的成績波動幅度很大，那么大多數(shù)的射擊成績離平均成績會比較遠。因此，我們可以通過這兩組射擊成績與它們的平均成績的“平均距離”來度量成績的波動幅度。
人教A版高中數(shù)學必修二事件的相互獨立性教學設計
問題導入：問題一：試驗1：分別拋擲兩枚質(zhì)地均勻的硬幣，A=“第一枚硬幣正面朝上”，B=“第二枚硬幣正面朝上”。事件A的發(fā)生是否影響事件B的概率？因為兩枚硬幣分別拋擲，第一枚硬幣的拋擲結果與第二枚硬幣的拋擲結果互相不受影響，所以事件A發(fā)生與否不影響事件B發(fā)生的概率。問題二：計算試驗1中的P(A),P(B),P(AB)，你有什么發(fā)現(xiàn)？在該試驗中，用1表示硬幣“正面朝上”，用0表示“反面朝上”，則樣本空間Ω={（1，1），（1，0），（0，1），（0，0）}，包含4個等可能的樣本點。而A={（1，1），（1，0）}，B={（1，0），（0，0）}所以AB={（1，0）}由古典概率模型概率計算公式，得P(A)=P(B)=0.5，P(AB)=0.25， 于是 P(AB)=P(A)P(B)積事件AB的概率恰好等于事件A、B概率的乘積。問題三：試驗2：一個袋子中裝有標號分別是1，2，3，4的4個球，除標號外沒有其他差異。
人教A版高中數(shù)學必修二立體圖形直觀圖教學設計
1.直觀圖：表示空間幾何圖形的平面圖形，叫做空間圖形的直觀圖直觀圖往往與立體圖形的真實形狀不完全相同，直觀圖通常是在平行投影下得到的平面圖形2.給出直觀圖的畫法斜二側畫法觀察：矩形窗戶在陽光照射下留在地面上的影子是什么形狀？眺望遠處成塊的農(nóng)田，矩形的農(nóng)田在我們眼里又是什么形狀呢？3. 給出斜二測具體步驟（1）在已知圖形中取互相垂直的X軸Y軸，兩軸相交于O，畫直觀圖時，把他們畫成對應的X'軸與Y'軸，兩軸交于O'。且使∠X'O'Y'=45°（或135°）。他們確定的平面表示水平面。（2）已知圖形中平行于X軸或y軸的線段，在直觀圖中分別畫成平行于X'軸或y'軸的線段。（3）已知圖形中平行于X軸的線段，在直觀圖中保持原長度不變，平行于Y軸的線段，在直觀圖中長度為原來一半。4.對斜二測方法進行舉例：對于平面多邊形，我們常用斜二測畫法畫出他們的直觀圖。如圖 A'B'C'D'就是利用斜二測畫出的水平放置的正方形ABCD的直觀圖。其中橫向線段A'B'=AB，C'D'=CD；縱向線段A'D'=1/2AD，B'C'=1/2BC；∠D'A'B'=45°，這與我們的直觀觀察是一致的。5.例一：用斜二測畫法畫水平放置的六邊形的直觀圖(1)在六邊形ABCDEF中，取AD所在直線為X軸，對稱軸MN所在直線為Y軸，兩軸交于O'，使∠X'oy'=45°（2）以o'為中心，在X'上取A'D'=AD，在y'軸上取M'N'=½MN。以點N為中心，畫B'C'平行于X'軸，并且等于BC；再以M'為中心，畫E'F'平行于X‘軸并且等于EF。 （3）連接A'B',C'D',E'F',F'A',并擦去輔助線x軸y軸，便獲得正六邊形ABCDEF水平放置的直觀圖A'B'C'D'E'F' 6. 平面圖形的斜二測畫法（1）建兩個坐標系，注意斜坐標系夾角為45°或135°；（2）與坐標軸平行或重合的線段保持平行或重合；（3）水平線段等長，豎直線段減半；（4）整理.簡言之：“橫不變，豎減半，平行、重合不改變?！?/p>
人教A版高中數(shù)學必修二平面與平面平行教學設計
1.探究：根據(jù)基本事實的推論2,3，過兩條平行直線或兩條相交直線，有且只有一個平面，由此可以想到，如果一個平面內(nèi)有兩條相交或平行直線都與另一個平面平行，是否就能使這兩個平面平行？如圖（1），a和b分別是矩形硬紙板的兩條對邊所在直線，它們都和桌面平行，那么硬紙板和桌面平行嗎？如圖（2），c和d分別是三角尺相鄰兩邊所在直線，它們都和桌面平行，那么三角尺與桌面平行嗎？2.如果一個平面內(nèi)有兩條平行直線與另一個平面平行，這兩個平面不一定平行。我們借助長方體模型來說明。如圖，在平面A’ADD’內(nèi)畫一條與AA’平行的直線EF,顯然AA’與EF都平行于平面DD’CC’,但這兩條平行直線所在平面AA’DD’與平面DD’CC’相交。3.如果一個平面內(nèi)有兩條相交直線與另一個平面平行，這兩個平面是平行的，如圖，平面ABCD內(nèi)兩條相交直線A’C’,B’D’平行。
人教A版高中數(shù)學必修二古典概型和概率的基本性質(zhì)教學設計
新知講授（一）——古典概型 對隨機事件發(fā)生可能性大小的度量（數(shù)值）稱為事件的概率。我們將具有以上兩個特征的試驗稱為古典概型試驗，其數(shù)學模型稱為古典概率模型，簡稱古典概型。即具有以下兩個特征：1、有限性：樣本空間的樣本點只有有限個；2、等可能性：每個樣本點發(fā)生的可能性相等。思考一：下面的隨機試驗是不是古典概型？（1）一個班級中有18名男生、22名女生。采用抽簽的方式，從中隨機選擇一名學生，事件A=“抽到男生”（2）拋擲一枚質(zhì)地均勻的硬幣3次，事件B=“恰好一次正面朝上”（1）班級中共有40名學生，從中選擇一名學生，即樣本點是有限個；因為是隨機選取的，所以選到每個學生的可能性都相等，因此這是一個古典概型。
人教A版高中數(shù)學必修二圓柱、圓錐、圓臺和球的表面積與體積教學設計
1.圓柱、圓錐、圓臺的表面積與多面體的表面積一樣，圓柱、圓錐、圓臺的表面積也是圍成它的各個面的面積和。利用圓柱、圓錐、圓臺的展開圖如圖，可以得到它們的表面積公式：2.思考1：圓柱、圓錐、圓臺的表面積之間有什么關系？你能用圓柱、圓錐、圓臺的結構特征來解釋這種關系嗎？3.練習一圓柱的一個底面積是S，側面展開圖是一個正方體，那么這個圓柱的側面積是（ ）A 4πS B 2πS C πS D 4.練習二：如圖所示，在邊長為4的正三角形ABC中，E，F(xiàn)分別是AB，AC的中點，D為BC的中點，H，G分別是BD，CD的中點，若將正三角形ABC繞AD旋轉180°，求陰影部分形成的幾何體的表面積．5. 圓柱、圓錐、圓臺的體積對于柱體、錐體、臺體的體積公式的認識(1)等底、等高的兩個柱體的體積相同．(2)等底、等高的圓錐和圓柱的體積之間的關系可以通過實驗得出，等底、等高的圓柱的體積是圓錐的體積的3倍．
人教A版高中數(shù)學必修二向量的減法運算教學設計
新知探究：向量的減法運算定義問題四：你能根據(jù)實數(shù)的減法運算定義向量的減法運算嗎？由兩個向量和的定義已知 即任意向量與其相反向量的和是零向量。求兩個向量差的運算叫做向量的減法。我們看到，向量的減法可以轉化為向量的加法來進行：減去一個向量相當于加上這個向量的相反向量。即新知探究（二）：向量減法的作圖方法知識探究（三）：向量減法的幾何意義問題六：根據(jù)問題五，思考一下向量減法的幾何意義是什么？問題七：非零共線向量怎樣做減法運算？ 問題八：非零共線向量怎樣做減法運算？1.共線同向2.共線反向小試牛刀判一判(正確的打“√”，錯誤的打“×”)(1)兩個向量的差仍是一個向量。 (√ )(2)向量的減法實質(zhì)上是向量的加法的逆運算. ( √ )(3)向量a與向量b的差與向量b與向量a的差互為相反向量。 ( √ )(4)相反向量是共線向量。 ( √ )
人教A版高中數(shù)學必修二復數(shù)的三角表示教學設計
本節(jié)內(nèi)容是復數(shù)的三角表示，是復數(shù)與三角函數(shù)的結合，是對復數(shù)的拓展延伸，這樣更有利于我們對復數(shù)的研究。1.數(shù)學抽象：利用復數(shù)的三角形式解決實際問題；2.邏輯推理：通過課堂探究逐步培養(yǎng)學生的邏輯思維能力；3.數(shù)學建模：掌握復數(shù)的三角形式；4.直觀想象：利用復數(shù)三角形式解決一系列實際問題；5.數(shù)學運算:能夠正確運用復數(shù)三角形式計算復數(shù)的乘法、除法；6.數(shù)據(jù)分析:通過經(jīng)歷提出問題—推導過程—得出結論—例題講解—練習鞏固的過程，讓學生認識到數(shù)學知識的邏輯性和嚴密性。復數(shù)的三角形式、復數(shù)三角形式乘法、除法法則及其幾何意義舊知導入：問題一：你還記得復數(shù)的幾何意義嗎？問題二：我們知道，向量也可以由它的大小和方向唯一確定，那么能否借助向量的大小和方向這兩個要素來表示復數(shù)呢？如何表示？
人教A版高中數(shù)學必修二平面與平面垂直教學設計
6. 例二：如圖，AB是⊙O的直徑，PA垂直于⊙O所在的平面，C是圓周上的一點，且PA＝AC，求二面角P－BC－A的大小． 解：由已知PA⊥平面ABC，BC在平面ABC內(nèi)∴PA⊥BC∵AB是⊙O的直徑，且點C在圓周上，∴AC⊥BC又∵PA∩AC=A,PA,AC在平面PAC內(nèi)，∴BC⊥平面PAC又PC在平面PAC內(nèi)，∴PC⊥BC又∵BC是二面角P-BC-A的棱，∴∠PCA是二面角P-BC-A的平面角由PA=AC知△PAC是等腰直角三角形∴∠PCA=45°，即二面角P-BC-A的大小是45°7.面面垂直定義一般地，兩個平面相交，如果它們所成的二面角是直二面角，就說這兩個平面互相垂直，平面α與β垂直，記作α⊥β8. 探究：建筑工人在砌墻時，常用鉛錘來檢測所砌的墻面與地面是否垂直，如果系有鉛錘的細繩緊貼墻面，工人師傅被認為墻面垂直于地面，否則他就認為墻面不垂直于地面，這種方法說明了什么道理？
人教A版高中數(shù)學必修二空間點、直線、平面之間的位置關系教學設計
9.例二：如圖，AB∩α=B,A?α， ?a.直線AB與a具有怎樣的位置關系？為什么？解：直線AB與a是異面直線。理由如下：若直線AB與a不是異面直線，則它們相交或平行，設它們確定的平面為β，則B∈β， 由于經(jīng)過點B與直線a有且僅有一個平面α，因此平面平面α與β重合，從而 , 進而A∈α，這與A?α矛盾。所以直線AB與a是異面直線。補充說明：例二告訴我們一種判斷異面直線的方法：與一個平面相交的直線和這個平面內(nèi)不經(jīng)過交點的直線是異面直線。10. 例3 已知a，b，c是三條直線，如果a與b是異面直線，b與c是異面直線，那么a與c有怎樣的位置關系？并畫圖說明．解： 直線a與直線c的位置關系可以是平行、相交、異面．如圖(1)(2)(3)．總結：判定兩條直線是異面直線的方法(1)定義法：由定義判斷兩條直線不可能在同一平面內(nèi)．
