懂你英语L4 Unit 2

L4Unit2-1Listening物种、环境Theearthwasbornabout4.6millionyearsago.Thefirstlifeappearedaboutabillionyearslater.Thefirstplantdidn’tappearuntilaround2billionyearsago.Untilaround580millionyearsago,lifeformedweresmallandmicroscopic(微笑的).Sincethattime,liveshasevolvedtomanydifferenttypesandspecies.However,scientistsestimatethatmorethan99%ofthemarenowextinct.Theyhavebeenseveralextinctioneventsinthehistoryoftheearth.Intheextinctionevent,manylifeformsorspeciesoflifedieout.Thecausesofthemassiveextinctioneventsareunsoughtmystery.Theseeventsarenotpredictableandcanhappenatanytime.Scientiststhinkthatsomeofthatstartedbyasteroidpassorvolcanocorruption.Eventslikethis,canchangetheglobalconditionsthatlifedependson.Onemajorextinctionevent,happenedabout66millionyearsago.Thateventmayhavebeenstartedbyalargeasteroidthathittheearth.Asaresult,thedinosaursandabouthalfoftheallspeciesontheplanet,diedout.Whentheasteroidhittheearth,itstartedachainofevents.Achainofeventisaseriesofeventslinkedtogether,likeachain.Theseparticularchainofeventshappenedoveraperiodofmonthsandyears.Whentheasteroidhittheearth,itcausedhugecloudofdusttoentertheatmosphere.Thiscloudofdustblockedthesunanddarkentheearthforaperiodofmonths.Withoutenoughsunlight,plantsandplant-eatinganimals,quicklydied.Withthedeathsofsomanyplantsandanimals,thefoodchaincollapsed.Thisledtothedeathsofmanymorespecies.Massextinctioneventshadplayedimportantpartintheevolutionoflife.Infact,someextinctioneventshadhelpedtoaccelerateevolution.Forexample,somemammalslivedtotheageofdinosaurs,buttheycouldn’tcompete.Whenthedinosaurswereremoved,themammalswereabletocompetemoresuccessfully.Oncetheycouldcompete,mammalevolvedtoahigherstate.Withouttheextinctionevent,perhapswewouldn’tbeheretoday.Scientistestimatethattherehavebeenatleast5massiveextinctionsinthepass540millionyears.Theyalsobelievedthatwehadenteredanewextinctionevent.Speciesarebecomingextinctatamuchfasterratethanbefore.Insteadoftheasteroidandvolcanocorruptions,thecurrenteventistheresultofhumanactivities.Humanactivities,forexample,hadledtoglobalwarming.Globalwarmingistheresultofanincreaseincarbongasesinouratmosphere.Thesegasestrapheatfromthesun,sotheearthisgettingwarmer.Asaresult,sealevelsarerisingandweatherpatternsarechanging.Inaddition,wehumansaredestroyinghabitatsofmanyplantsandanimals.Cuttingdownforestandpollutingriversdestroysthehabitatsofmanyformsoflife.Thereisnolongeranydoubtthatthisishappening.Specialsoflivesaredisappearingatanincreasingrate.Globaltemperaturesarerisingandweatherpatternsarechanging.Scientistsarewarningusthatfastactionisnecessarytosaveourfuture.Ifwedon’tact,wemaygothewayofthedinosaurs.L4Unit2-1vocabulary身体系统、产业、技术Thebodycirculatorysystemincludestheheartandbloodvessels.Theheartpumpsthebloodstoallpartsofbodythroughanetworkofarteriesandvein.Thedigestivesystembreaksdownandabsorbsfoodintothebody.Itsuppliestheenergythatthebodyneedsforgrowthandrepair.Afterdigestion,excessfoodisturnedintowasteandeliminatedfromthebody.Thenervoussystemincludesthebrain,spinalcordandnerves.Thisisyourcontrolsystem.Itcontrolsyourmusclesandorgansincludedyourcirculatorysystemanddigestivesystem.Therespiratorysystemincludesyournoseandlungs.Itbringsairandoxygenintoyourbodyandremovethecarbondioxidefromthebody.Thelungsarewhereoxygenentersthebloodstreamandcarbondioxideisremoved.Immunesystemprotectsbodyagainsttheinfectionsanddiseases.Sneezingandfeverareexamplesofhowtheimmunesystemsworks.Iftheinfectioninvadesthebodyandtheimmunesystemattacksit.Thecontroluseoffireallowedpeopletocookfoodandsurviveinthecolderclimates.Fireprovidedthelightsothatpeoplecouldworkandsocializeforlongerhours.Withtheinventionofagriculture,peoplecangrowfoodandsettleintocommunities.Bygrowingfood,peoplecanspendlesstimehuntingandmoretimeonotherthings,suchasart.Thedomesticationofanimalsallowspeopletoraiseanduseanimalsforfoodandwork.Byraiseherdsofanimals,suchassheep,peoplehaveregularsupplyofmeatandclothing.Thestrengthofanimalssuchashorsesandoxenwasusedforworkandtransportation.Thedevelopmentoftoolsandmachineshasresultedinamorefashionmanufacturingandconstruction.Withbettertoolsandmachines,workscanbedonewithfewerpeopleandmuchlowercost.Thedevelopmentofscienceandengineeringhasimprovedmanythingincludingcommunications.Withunderstandingofelectricity,telephoneandradiosallowpeopletocommunicateoverlongdistances.Theuseofmachineshasreducedthenumberofpeopleneededtomakethings.L4Unit2-1dialogue谈论手机和老板Itookavacationlastnight.Whatareyoutalkingabout.Wheredidyoutakethevacation.Ididn’tgoanywhere.ijustleftwithmysmartphone.Howwasit.Itwasgreat.Igotarealmagazineandreaditwithnointerpretation.Itwasverypeaceful.Yes,Ihaven’tdonethatforalongtime.Youknowwhat,Ibegintohatesmartphone.Really,butyoucan’tlivewithoutone,right.Yes,that’stheproblem.Thischangethewaypeoplelive.Yes,Ijustsoondocumentaryaboutthat.Ahusbandwascomplaininghiswifethatshewasspendingtoomuchtimeonhersmartphone.Whathappened,didtheygetdivorced.Youguessit.Intheend,theygotdivorced.Itisabitironic,don’tyouthink.Smartphonesweresupposedtobringpeopletogetherbuttheyarepullingpeopleapart