冀教版九年级全册Unit5Lesson29教案

Unit5LookintoScienceLesson29【教学目标】1．记忆单词DNA,blueprint,general,complex,twin,repeat,pattern,identify,related,grandson,granddaughter,instruction;短语ingeneral,exceptfor,erelatedto,billionsof.2．掌握重点句型:（1）Ingeneral,blueprintisadrawingthatshowshowtoputahousetogetherwithmanydifferentparts.（2）Butbuildingalivingthingisfarmorecomplexthanbuildingahouse.（3）YouhaveyourownuniqueDNA,butitrepeatspatternsfromyourparents'DNA.（4）FromyourDNA,scientistscanidentifynotonlyyou,butalsopeoplewhoarerelatedtoyou.3．能够用英语向他人介绍自己所知道的有关DNA的知识.4．能够理解课文内容并回答课后的问题.【教学内容】1．学会并能正确使用单词及短语:DNA,blueprint,general,complex,twin,repeat,pattern,identify,related,grandson,granddaughter,instruction,ingeneral,exceptfor,berelatedto,billionsof.2．能够运用下列句型:（1）Ingeneral,blueprintisadrawingthatshowshowtoputahousetogetherwithmanydifferentparts.（2）Butbuildingalivingthingisfarmorecomplexthanbuildingahouse.（3）YouhaveyourownuniqueDNA,butitrepeatspatternsfromyourparents'DNA.（4）FromyourDNA,scientistscanidentifynotonlyyou,butalsopeoplewhoarerelatedtoyou.【教学重难点】1．能够正确应用本课的重点词汇:DNA,blueprint,general,complex,twin,repeat,pattern,identify,related,grandson,granddaughter,instruction;掌握短语ingeneral,exceptfor,berelatedto,billionsof.2．能够用英语向他人介绍自己所知道的有关DNA的知识.【教学思路】思路一:以"DNA"为主题.通过展示图片,询问学生们"他们看起来一样吗?为什么一样?他们?为什么不同?"引导学生们发现他们看起来相似的原因是由于DNA.通过设置学,激发他们的学习兴趣,调动他们的积极性和主动性:以"DNA"为主题.通过师生对话,直接导入本课话题DNA.通过小组合作探究,共同解决疑难看起来不同吗生感兴趣的话题导入新课.思路二,找出文中的重点短语和句子.【教学准备】教师在课前设计教学PPT,准备录音机和磁带,多媒体等.【教学过程】Ⅰ．LeadinLeadingin情景1T:Hello,class.Todaywe'lllearnLesson29.(TheteachershowstwopicturesonPPT.)Pleaselookatthepictures.Aretheylookthesame?Aretheredifferencesbetweenthem?S1:...T:Whydosomestudentslookdifferent?Andwhydocousinslooksimilar?Ss:BecauseofDNA.T:Welldone.Nowlet'slearnLesson29:DNA—TheStoryofYou.设计意图:通过展示图片,设置学生感兴趣的问题,引出本课话题——DNA.激发了学生的学习兴趣.Leadingin情景2T:Goodmorning/afternoon,everyone.WhatisDNA?WhatdoesDNAstandfor?S1:DNAissomethingthatalllivingthingshave.S2:DNAcarriesthegeneticinformationthatmakeseverylivingthingwhatitis.T:Verygood.DNAisshortforthefullscientificterm"deoxyribonucleicacid".That'shardtosay.DNAismucheasier.EverylivingthinghasitsownDNA.DNAholdstheinformationandinstructionsforcreatingalivingthing.Forexample,IhavestraightblackhairbecausepartoftheinstructionsinmyDNAwastogivemestraightblackhair.Mygrandmotherhasthesamestraightblackhair.Ihavepartofmygrandmother'sDNA.设计意图:教师采用直接导入的方法,引出本课话题——DNA,使学生很直观地进入本课的学习,为下面的学习奠定基础.Ⅱ．PresentationTheteachershowsthenewwordsonPPT.Askstudentstotrytoreadthesewords.Thestudentsfollowtheteacherthreetimes.Thengivethestudentsfiveminutestorememberthewords.Letstudentsspellandreadthemonebyone.设计意图:教师以PPT的形式呈现本课中出现的生词,领着学生们朗读并记忆,为下面的课文学习做好充分准备.Ⅲ．Reading1．Readthetextaloud.T:Boysandgirls,it'sourreadingtime.Pleasereadafterthevideoandyoushouldpaymoreattentiontoyourpronunciation.设计意图:让学生大声朗读课文,对课文的意思有个大致的了解,对于培养学生的正确发音以及培养学生的语感都有重要作用.2．Carefulreading.T:Boysandgirls,nowthistime,I'llmaketheexercisealittlemoredifficult.Readthelessonagainandanswerthequestions.ShowLet'sDoIt!Readthelessonandanswerthequestions.（1）Whatisablueprint?（2）Whichismorecomplex,buildingalivingthingorbuildingahouse?（3）DosometwinshavethesameDNA?（4）IsitpossibletochangeyourDNA?（5）WhoseDNAisrelatedtoyours?Keys:（1）Ablueprintisadrawingthatshowshowtoputahousetogetherwithmanydifferentparts.（2）Buildingalivingthingisfarmorecomplexthanbuildingahouse.（3）Yes,theydo.（4）Yes,itis.Inthefuture,scientistsmightbeabletochangeourDNA.（5）Peoplewhoarerelatedtome.Forexample,myparentsandgrandparents.设计意图:要求学生认真阅读课文,把握课文信息,回答问题,对文章内容有更深层次的理解.3．Readthetextandfindoutmainphrasesandsentences.Mainphrases:IngeneralExceptforBerelatedtoBillionsofMainsentences:WhatcanscientistsdowithDNA?Butbuildingalivingthingisfarmorecomplexthanbuildingahouse.Exceptforsometwins,everylivingthinghasitsownuniqueDNA.SomehealthproblemscanbecausedbyproblemsinyourDNA.Inthefuture,scientistsmightbeabletochangeyourDNA.TherearecopiesofyourDNAineverypartofyourbody.YouhaveyourownuniqueDNA,butitrepeatspatternsfromyourparents'DNA.YourDNAhasbillionsofinstructionsthatexplainwhyyouarethewayyouare.It'soneofthemostamazingthingsontheearth!教材解读:（1）WhatcanscientistsdowithDNA?dowith为固定短语,意为"处理",强调对象拓展:dealwith也意为"对待,处理",侧重处理的方式（2）Ingeneral,ablueprintisadrawingthatshowshowtoputahousetogetherwithmanydifferentparts.ingeneral意为different为形容词,意为bedifferentin…在……上不同.（3）Butbuildingalivingthingisfarmorecomplexthanbuildingahouse.,与疑问词what连用.、方法,与疑问词how连用."一般而言,概括说来",通常置于句首,也可以用generallyspeaking来表示."不同的",常用于以下结构中:bedifferentfrom与……不同;living为形容词far为副词,意为"非常,远远:同样用法的词还有even"甚至lot"……得多"等等（4）Exceptforsometwins,everylivingthinghasitsownuniqueDNA.exceptfor意为"除……之外",它要求排除的是不同类的:exceptfor,except,besides,butexceptfor意为"除了",表示对主体的肯定和局部的否定except可用作介词,意为"除了……之外",表示同类事物间的排除关系besides可用作介词,意为"除……之外",表示同类事物间的叠加关系but可用作介词,意为"除……之外",常与no,all,every,each,none,nobody等词连用与except互换every为形容词,意为"作主语时,谓语动词用单数;every强调整体概念,不能直接与拓展:each可作形容词,意为"每个的",也可用作代词语,其后接单数名词;"each+单数名词"或each作主语时,谓语动词用单数each强调个体,可与of连用,指两者及两者以上中的每一个注意:"every/each+单数名词+and+every/each+单数名词"结构作主语时式.own作形容词,意为",用来修饰形容词和副词的比较级";rather"相当";much"……得多"活着的,活的",常作定语.,表示程度.拓展";alittle/bit"有点";a..辨析,用于不同类的事物间...,有时可."每一的,每一个的of连用,意为",其后接单数名词;"every+单数名词,指三者及三者以上中的每一个"每个",each作形容词时只能作定.;.,谓语动词用单数形,意为"自己的",位于物主代词或名词所有格之后,还可作动词,意为"拥有",其,其名词形式为owner,意为"物主（5）SomehealthproblemscanbecausedbyproblemsinyourDNA.health为不可数名词,意为"健康",常构成短语ingood/badhealth,意为后宾语多表示房屋、土地或财产等"."健康/不健康".拓展:healthy为形容词,意为"健康的";unhealthy意为"不健康的",keep/stayhealthy意为"保持健康".healthily为副词cause为及物动词,意为语.拓展:cause作名词用.,意为"健康地",eathealthily意为"吃得健康".,也可接动词不定式作宾语补足"引起,导致,发生",后面可接双宾语,意为"原因、起因".指导致某种结果、造成一种事实的原因,通常与of连（6）Inthefuture,scientistsmightbeabletochangeyourDNA.beableto意为"能,会",表示通过努力而获得的能力,强调结果,可用于各种时态,其后接动词原形.（7）YouhaveyourownuniqueDNA,butitrepeatspatternsfromyourparents'DNA.repeat为及物动词,意为"重复,重述",后接名词或代词作宾语.parents'意为"父母亲的",是复数名词的所有格形式.（8）FromyourDNA,scientistscanidentifynotonlyyou,butalsopeoplewhoarerelatedtoyou.identify为及物动词,意为"确认,识别,鉴别",后接名词或代词作宾语.berelatedto意为"和……有联系,和……有关,与……有亲戚关系".related为形容词,意为"有关的、相关的".relate为动词,意为"把……联系起来",常与to或with搭配.（9）YourDNAhasbillionsofinstructionsthatexplainwhyyouarethewayyouare.本句句末的youare是theway的定语从句.theway的定语从句的引导词可用inwhich,或用that,也可以不用引导词.way在本句中意为"情况、状态".（10）It'soneofthemostamazingthingsontheearth!oneofthemostamazingthings意为"最令人惊奇的事情之一",为"oneofthe+形容词的最高级+复数名词"结构.其中定冠词the也可使用形容词性的物主代词来代替.设计意图:学生是学习的主体,教师要努力调动学生学习的积极性和主动性,通过组内合作讨论、探究,找出课文中的关键单词、短语和句子,把所学的知识转化为学习能力.Ⅳ．Task1．ShowLet'sDoIt!IsitagoodideatochangetheDNAofthefoodweeat?Somepeoplesaydoingthismakesourfoodbetter.Othersthinkit'stoodangerous.SearchtheInternetforinformationandwritedownyourideas.2．HavethestudentsconsiderthequestionsinLet'sDoIt!No.4.3．Havethemcompletethistaskandresearchgeneticallymodifiedfood.Theirresearchshouldanswerthefollowingquestions:Doyouthinkit'sagoodideatochangetheDNAofthefoodweeat?Whyorwhynot?Whataresomeofthepositivesofgeneticallymodifiedfood?Whataresomeofthenegativesofgeneticallymodifiedfood?4．Havethegroupspresenttheirresearchintheformofacommercialthatiseitheradvertisingthecontinuationofgeneticallymodifiedfoodortheendofit.:锻炼学生的口语表达与写作能力,同时培养学生的合作意识设计意图.Ⅴ．Practice1．ShowLet'sDoIt!No.2.Fillintheblankswiththephrasesinthebox.ingeneral,exceptfor,notonly…butalso,relatedto,evenif,thesame…as…（1）Yourhomeworkisquitegood______afewspellingmistakes.（2）______theyoung______theoldlikepopmusic.（3）Kate'shairis______color______hersister's.（4）______,womenlivelongerthanmen.（5）______manydifficultiesremain,wecanovercomethem.（6）Iswealth______happiness?2．Completethepassagewiththesentencesinthebox.ChangingDNADoyouknowDNAcanbechanged?Haveyoueverseenapigwithadog'sbody?Ofcoursenot!Pigsanddogscan'thavebabiestogether.______butnow,scientistscandoit.ScientistscantakeDNAfromonekindofanimalandputitintoanotherkindofanimal.TheycandesignnewplantsbycombiningtheDNAofotherplants.______Somescientistsareworried.TheysayweneedtoknowmoreaboutDNAbeforewestartchangingit.______Butwhatiftheplantsarebadforhumans,too?A．TheirDNAcan'tcombine.