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Unit4Astronomy:thescienceofthestarsHowmuchdoyouknowabouttheuniverse?Whatarethenamesoftheeightplanetsthatcircleoursun?Whatistheirorderfromthesun?地球______木星______火星______水星________海王星_______土星________天王星_______金星________EarthJupiterMarsMercuryNeptuneSaturnUranusVenusTHESOLARSYSTEM1.Howoldistheuniverse?2.Howoldistheearth?3.Whichwerethefirstcreatureorplantsonearth?4.Doyouknowwhattheorderforthedevelopmentofplantsandanimalsis?Severalbillionyearsago.Between4.5and3.8billionyearsago.Verysmallair-breathingcreatures.FreeTalkIdeasabouthowlifebeganreadingHowLifeBeganontheEarthFastreadingReadthepassagequicklyandfindthemainidea.Abriefintroductiononhowtheuniversedevelopedandhowlifebeganontheearth.CarefulreadingPara1:Para2:Para3:Para4:Para5:Awidelyacceptedtheoryabouttheformationoftheuniverse.Theformationoftheearth.Theimportanceofwaterforlife.Thedevelopmentofplantsandanimalsontheearth.Thearrivalofhumansandtheirimpactontheearth.Readthepassagecarefullyandanalyseitsstructure.earth,atmosphereandwaterlifedevelopmenthumanbeings1.Whatistheoriginalearth’satmospheremadeupof?2.Whydidscientistsbelievewaterisfundamentaltothedevelopmentoflife?3.Howdidwatercomeintobeingontheearth?4.Whichkindoflife-beingfirstappearedontheearth,plantsoranimals?Why?5.Whyweremammalsdifferentfromalllifeformsinthepast?Answerthefollowingquestions.Carbon,nitrogen,watervapour,andothergases.2.Whydidscientistbelievewaterisfundamentaltothedevelopmentoflife?Becausewaterallowedtheearthtodissolveharmfulgasesandacidsintotheoceansandseastoensureafollowingchainreaction,whichmadeitpossibleforlifetodevelop.1.Whatistheoriginalearth’satmospheremadeupof?3.Howdidwatercomeintobeingontheearth?Theexplosionoftheearthproducedwatervapor,whichturnedintowaterwhentheearthcooleddown.4.Whichkindoflife-beingfirstappearedontheearth,plantsoranimals?Why?Atfirst,smallplantsbegantoappearonthesurfaceofthewater,theyproduceoxygen,whichencouragedthelaterdevelopmentofearlyshellfishandallsortsoffish.5.Whyweremammalsdifferentfromalllifeformsinthepast?Theyweredifferentbecausetheyproducedtheiryoungfromwithintheirbodiesandproducemilktofeedthem.•（）1Insectsandamphibiansappeared.•（）2Dinosaursappeared.•（）3Theearthbecameasolidball.•（）4Smallplantsgrewonthewater.•（）5Reptilesappeared.•（）6Plantsbegantogrowondryland.•（）7Theearthwasacloudofdust.•（）8Waterappearedontheearth.•（9Shellfishandotherfishappeared.•（）10Theuniversebeganwitha“BigBang”.•（）11Cleveranimalswithhandsandfeetappeared.•（）12Mammalsappeared.875）64110392Puttheorderofdevelopmentoflife.1211Letreviewtheevolutionoflifeontheearth.Afterthe“BigBang”,theearthwasfullofwater.Originalcellsappearedintheocean.Thecellsinthewaterbegantoseparate.Smallplantscameintobeing.EarlyshellfishandallsortsoffishSomeanimals(amphibian&insects)cametoland.Reptileappeared.dinosaursmammalsManhadevolvedfromapes.Wearemakingtheworldbetter.Wearemakingtheworldworse.DiscussionBecausetheyareputtingtoomuchcarbondioxideintotheatmosphere.Theearthmaybecometoohottoliveon.Theearthisbecominghotterandhotter!solarenergyplanttreesrecyclerubbishpreventdesertificationsavewaterpurifyairWhatcanwedototakecareoftheearth?Whetherlifewillcontinueontheearthdependsonhumanbeings.精讲点拨•Theearthbecamesoviolentthatitwasnotclearwhethertheshapewouldlastornot.•Whatmanyscientistsbelieveisthatthecontinuedpresenceofwaterallowedtheearthtodissolveharmfulgasesandacidsintotheoceans.分析句子：Homework1.AcompositionaboutWhatwecandototakecareoftheearth?2.Readandretellthepassagetolearntheimportantanddifficultlanguagepoints.