人教必修三unit4课文精讲.pptx

人教必修三unit4课文精讲.pptx

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ModuleIIIUnit4,Astronomy,抄写,asaresult结果asaresultof.由于.的结果too.to.太.而不能.dependon依赖，取决于lookafter照顾prevent.from（doing）.阻止.做.escapefrom.逃离.inonesturn轮到某人，接着,bedifferentfrom.与.不同givebirthto.产生；分娩layeggs下蛋allowdoing允许做某事allowsb.todo允许某人做某事beallowedtodo被允许做某事befundamentalto对.是重要的intime及时ontime按时accordingto根据beginwith起源于inalldirections=朝四面八方,Whatsthemeaningoftheword“Astronomy”?

I.Warmingup,thescienceofstars;thescientificstudyofstarsandplanets.,2.Whatwordswillyouthinkofwhenwetalkaboutthistopic?

star,planet,thesun/moon/earth,solarsystem,恒星行星太阳月球地球太阳系,3.Howmanyplanetsareinthesolarsystem?

8,Pluto,ScientistsnowthinkPlutoistoosmalltobecalledaplanet.,TheSolarSystem,1111,5.Thenamesofeightplanets.,MercuryVenusEarthMarsJupiterSaturnUranusNeptune,1）水星2）金星3）地球4）火星5）木星6）土星7）天王星8）海王星,II.Pre-reading,Haveyoueveraskedyourmother,“Mom,wheredoIcomefrom”?

2.Nearlyeverybodyhasthisorthatpuzzles:

Howdohumanbeingscomeintobeing?

Howdoestheearthcomeintobeing?

3.InChina,therearetwolegendsaboutthesepuzzles.Doyouknowthenames?

盘古开天辟地女娲补天造人,4.Inthewesternculture,whocreateseverythingintheworld?

TheGod,III.Fast-reading,Doyoubelieveinsuchstories?

Aretheybasedonscience?

2.Inthisunit,welllearnsomethingmorescientific.3.Whatsthetitleofthetext?

4.Fromthetitle,wecanpredictthatthetextmaytellustheoriginoflifeontheearth.,Howlifebeganontheearth,5.Letsenjoyashortvideo.生命进化史,HOWLIFEBEGANONTHEEARTH地球上生命的起源,Nooneknowsexactlyhowtheearthbegan,asithappenedsolongago.However,accordingtoawidelyacceptedtheory,theuniversebeganwitha“BigBang”thatthrewmatterinalldirections.Afterthat,atomsbegantoformandcombinetocreatestarsandotherbodies.没有人确切知道地球是怎样开始形成的，因为在很早很早以前它就形成了。

然而，一种普遍为人们所接受的理论是：

宇宙起源于一次大爆炸，这次大爆炸将物质投射到四面八方。

然后，原子开始形成并结合成恒星和其他天体。

1.accordingto根据2.widelyaccepted广泛接受的3.beganwith=startwith起源于，开始于4.inalldirections=朝四面八方,句型beginwith/startwith以开始，从着手仿写认识从实践开始。

Knowledge_.,beginswithpractice,Forseveralbillionyearsafterthe“BigBang”,theearthwasstilljustacloudofdust.Whatitwastobecomewasuncertainuntilbetween4.5and3.8billionyearsagowhenthedustsettledintoasolidglobe.Theearthbecamesoviolentthatitwasnotclearwhethertheshapewouldlastornot.Itexplodedloudlywithfireandrock.大爆炸后好几十亿年过去了，但地球还只是一团尘埃。

随后它会变成什么没人能知道，直到38-45亿年前，这团尘埃才慢慢地形成一个固体的球状物。

地球（开始）变得激烈动荡，不知道这个固体形状是否会继续存在下去。

它（地球）猛烈的爆炸喷出了烈火与岩石。

Itwasnotclearwhether.“是否.是不清楚的”，it是形式主语，whether从句为真正的主语，即Whethertheshapewouldlastornotwasnotclear.,what引导的主语从句，what作become的表语，when引导的是定语从句，修饰between4.5and3.8billionyearsago。

一团,不确定的，certain确定的,vi.持续,vilent激烈的，violence暴力,2.Whatitwastobecomewasuncertainuntilbetween4.5and3.8billionyearsagowhenthedustsettledintoasolidglobe.,_（使大家吃惊的是）isthathedidntcometothemeeting.,Whatsurprisedeverybody,2._（他所做的）addedtoourdifficulty.,Whathedid,_wecantgetseemsbetterthan_wehave.What;whatB.What;thatC.That;thatD.That;what_madetheschoolproudwas_morethan90%ofthestudentshadbeenadmittedtokeyuniversities.A.What;becauseB.What;that;C.That;whatD.That;because,A,B,Theywereintimetoproducecarbondioxide,nitrogen,watervapourandothergases,whichweretomaketheearthsatmosphere.Whatisevenmoreimportantisthatastheearthcooleddown,waterbegantoappearonitssurface.最终产生了碳、氮气、水蒸气和其他多种气体，从而形成了地球的大气层。

更为重要的是，地球冷却了下来，地球的表面就开始出现了水。

intime及时；终于intimetodosth及时做某事，来得及做某事ontime按时Whatisevenmoreimportantisthat.更为重要的是.cooldown凉下来，冷却,定语从句,2.Whatisevenmoreimportantisthatastheearthcooleddown，waterbegantoappearonitssurface.（P26L13）句式分析句中what引导的是一个_，what做从句主语，that引导的是一个_，as引导的是一个_。

时间状语从句,主语从句,表语从句,WaterhadalsoappearedonotherplanetslikeMarsbut,unliketheearth,ithaddisappearedlater.Itwasnotimmediatelyobviousthatwaterwastobefundamentaltothedevelopmentoflife.在火星这些其他行星上都出现了水，但和地球不同的是，这些水后来都消失了。

水会对生命的发展起关键作用，这一点在当时并不明显。

befundamentalto对.是重要的It是形式主语，真正的主语是thatwaterwastobefundamentaltothedevelopmentoflife.Itis/was（not）obviousthat.是（不）明显的，如:

Itisnowonderthathehaspassedtheexam.,Whatmanyscientistsbelieveisthatthecontinuedpresenceofwaterallowedtheearthtodissolveharmfulgasesandacidsintotheoceansandseas.Thisproducedachainreaction,whichmadeitpossibleforlifetodevelop.很多科学家相信，由于地球表面上长期有水存在，它使得地球得以把有害气体和酸性物质溶解在海洋里。

这就产生了一系列的反应，使得生命就有可能开始发展了。

thecontinuedpresenceofwater水的长期存在allowvt.允许、许可、容许allowdoing允许做某事allowsb.todo允许某人做某事beallowedtodo被允许做某事,主语从句,that引导表语从句,continued持续不断的,连锁反应,which引导定语从句,beharmfulto对有害,doharmtosb.=dosb.harm伤害某人，对某人有害处,1）Pollutionisespeciallyharmfultoanimals.,2）Smokingwilldoyoualotofharm.,Stage1:

Thedevelopmentoftheearth,

（1）AftertheBigBang,whatwastheearthlike?

acloudofdust,asolidglobe,explodedwithfireandrock,producedwatervapourandgases,

（2）Whathappenednext?

（3）Whatdidthewatervapourandgasesform?

theearthsatmosphere,Waterappeared,（4）Whatappearedastheearthcooleddown?

waterisimportantforthebeginningoflifeontheearth.,Whyiswatersoimportantforthebeginningoflife?

Becausewaterallowedtheearthtodissolveharmfulgasesintooceansandseas.,？

Manymillionsofyearslater,thefirstextremelysmallplantsbegantoappearonthesurfaceofthewater.Theymultipliedandfilledtheoceansandseaswithoxygen,whichencouragedthelaterdevelopmentofearlyshellfishandallsortsoffish.好几百万年以后，水的表面开始出现了极小的植物。

它们繁殖起来就使得早期的海洋充满了氧气，这为早期的贝类及其他各种鱼类的发育进一步创造了条件。

在.的表面,引导定语从句,各种各样的,Next,greenplantsbegantogrowonland.Theywerefollowedintimebylandanimals.Somewereinsects.Others,calledamphibians,wereabletoliveonlandaswellasinthewater.接着，绿色植物开始出现在陆地上。

随后，陆地上出现了动物，其中有一些是昆虫，另外一些叫两栖动物，它们既能在陆地上生活，也能在水里生活。

也，又，还,被称为两栖动物,Laterwhentheplantsgrewintoforests,reptilesappearedforthefirsttime.Theyproducedyounggenerallybylayingeggs.Afterthat,somehugeanimals,calleddinosaurs,developed.Theylaideggstooandexistedontheearthformorethan140millionyears.后来当这些植物长成森林时，爬行动物第一次出现了。

它们一般是通过孵蛋来繁衍后代的。

再后来一些叫做恐龙的巨型动物出现了。

它们也生蛋，在地球上生存了一亿四千多年。

14.Theyproducedyounggenerallybylayingeggs.它们一般是通过孵蛋而繁衍后代的.Lie,lie,lay的区别如下:

However,65millionyearsagotheageofthedinosaursended.Whytheysuddenlydisappearedstillremainsamystery.Thisdisappearancemadepossibletheriseofmammalsontheearth.然而，六千五百万年前，恐龙时代结束了。

它们为什么会突然灭绝至今仍是个谜。

恐龙的灭绝使地球上哺乳动物的产生有了可能。

appear-disappearappearance-disappearance,Theseanimalsweredifferentfromalllifeformsinthepast,becausetheygavebirthtoyoungbabyanimalsandproducedmilktofeedthem.这些动物不同于以往所有的生命形态，因为它们能从体内生产出幼仔并给幼仔哺乳。

bedifferentfrom.与.不同givebirthto.产生；分娩,比较两处的form,“atomsbegantoform”,Finallyabout2.6millionyearsagosomesmallcleveranimals,nowwithhandsandfeet,appearedandspreadallovertheearth.Thustheyhave,intheirturn,becomethemostimportantanimalsontheplanet.最后，大约260万年前，一些小巧聪明、长着手脚的动物出现了，它们散布在地球的各个地方。

于是，他们接着成为了这个行星上最重要的动物。

inonesturn轮到某人，接着,Buttheyarenotlookingaftertheearthverywell.Theyareputtingtoomuchcarbondioxideintotheatmosphere,whichpreventsheatfromescapingfromtheearthintospace.然而，他们对地球却并不怎么在意。

它们把过多的二氧化碳释放到大气层中，这使得地球上的热不能释放到太空中去。

lookafter照顾prevent.from（doing）.阻止.做.escapefrom.逃离.,16.Theyareputtingtoomuchcarbondioxideintotheatmosphere,whichpreventsheatfromescapingfromtheearthintospace.,阻止某人做某事:

preventsb.（from）doingsth.,stopsb.（from）doingsth.,keepsb.fromdoingsth.,Asaresultofthis,manyscientistsbelievetheearthmaybecometoohottoliveon.Sowhetherlifewillcontinueontheearthformillionsofyearstocomewilldependonwhetherthisproblemcanbesolved.因此很多可科学家相信地球可能会因此变得太热而不适合生物的生存。

所以，在未来的数百万年中，生命能否在地球上延续取决于这个问题能否得到解决。

asaresult结果asaresultof.由于.的结果too.to.太.而不能.dependon依赖，取决于,主语从句,宾语从句,Stage2Thedevelopmentoflife,smallplantsappearsinwater,1.Whatlifedevelopedafterwaterappeared?

Shellfishandallsortsoffish,2.Whatlifedevelopedinwaternext?

greenplantsbegantogrowonland,insectsappeared,3.Whataboutthelifeonland?

amphibiansonlandandinthewater,forests,4.Whatlifedevelopednextonland?

reptilesappeared,dinosaurdeveloped,5.Whatlifedevelopedafterforestsappeared?

mammalsonland,6.Whatlifedevelopedafterdinosaurs?

smallcleveranimals,7.Whatlifedevelopedaftermammals?

1.Whoarethesmallcleveranimalswithhandsandfeet?

2.Aretheytakingcareoftheearthwell?

Why?

?

Becausetheyareputtingtoomuchcarbondioxideintotheatmosphere,whichpreventsheatfromescapingfromtheearthintospace.,Theearthmaybecometoohottoliveon.,Theearthisbecominghotterandhotter!

1.Insectsandamphibiansappeared.3.Theearthbecameasolidball.5.Reptilesappeared.7.Theearthwasacloudofdust9.Shellfishandotherfishappeared.11.Cleveranimalswithhandsandfeetappeared,2.Dinosaursappeared.4.Smallplantsgrewonthewater.6.Plantsbegantogrowondryland.8.Waterappearedontheearth10.Theuniversebeganwitha“BigBand”.12.Mammalsappeared.,8,3,10,9,11,5,1,7,4,12,6,2,Canyouputtheorderofdevelopmentoflifeintoatimeline?

Ex.2onP27,1.Thereisa_（fundament）differenceinattitudebetweenthesetwopoliticians.2.Hedidntbelieveinthe_（exist）ofGod.3.Its_（like）himnottosayhello;asheisamaningoodmanners.4.Itis_（harm）toyoureyestoreadinbed.,五、词形变换用所给词的适当形式填空。

harmful,fundamental,existence,unlike,