流利说懂你英语Level4Unit2.docx

流利说懂你英语Level4Unit2.docx

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流利说懂你英语Level4Unit2

Level4Unit2Part1Listening-ExtinctionEvents1

TheEarthwasformedabout4.6billionyearsago.

Thefirstlifeappearedaboutabillionyearslater.

Thefirstplantsdidn'tappearuntilaround2billionyearsago.

Untilabout580millionyearsago,lifeformsweresmallandmicroscopic.

Sincethattime,lifehasevolvedintomanydifferenttypes,orspecies.

However,scientistsestimatethatmorethan99%ofthemarenowextinct.

TherehavebeenseveralextinctioneventsinthehistoryoftheEarth.

Inanextinctioneventmanylifeforms,orspeciesoflife,dieout.

Thecausesofmassextinctioneventsareunsolvedmysteries.

Theseeventsarenotpredictableandcanhappenatanytime.

Scientiststhinkthatsomeofthemwerestartedbyasteroidimpactsorvolcaniceruptions.

Eventslikethesecanchangetheglobalconditionsthatlifedependson.

Onemajorextinctioneventhappenedabout66millionyearsago.

ThateventmayhavebeenstartedbyalargeasteroidthathittheEarth.

Asaresult,thedinosaursandabouthalfofallspeciesontheplanetdiedout.

Whentheasteroidhittheearth,itstartedachainofevents.

Achainofeventsisaseriesofeventslinkedtogether,likeachain.

Thisparticularchainofeventshappenedoveraperiodofmonthsandyears.

WhentheasteroidhittheEarth,itcausedahugecloudofdusttoentertheatmosphere.

ThiscloudofdustblockedthesunanddarkenedtheEarthformanymonths.

Withoutenoughsunlight,plantsandplant-eatinganimalsquicklydied.

Withthedeathsofsomanyplantsandanimals,thefoodchaincollapsed.

Thisledtothedeathsofmanymorespecies.

Massextinctioneventshaveplayedanimportantpartintheevolutionoflife.

Infact,someextinctioneventshavehelpedtoaccelerateevolution.

Forexample,somemammalslivedthroughtheageofthedinosaurs,buttheycouldn'tcompete.

Whenthedinosaurswereremoved,themammalswereabletocompetemoresuccessfully.

Oncetheycouldcompete,mammalsevolvedtoahigherstate.

Withoutextinctionevents,perhapswewouldn'tbeheretoday.

Level4Unit2Part1Listening-ExtinctionEvents2

Scientistsestimatethattherehavebeenatleast5massextinctionsinthelast540millionyears.

Theyalsobelievethatwehaveenteredanewextinctionevent.

Speciesarebecomingextinctatamuchfasterratethanbefore.

Insteadofasteroidsorvolcaniceruptions,thecurrenteventistheresultofhumanactivities.

Humanactivities,forexample,haveledtoglobalwarming.

Globalwarmingistheresultofanincreaseincarbongasesinouratmosphere.

Thesegasestrapheatfromthesun,sotheEarthisgettingwarmer.

Asaresult,sealevelsarerisingandweatherpatternsarechanging.

Inaddition,wehumansaredestroyingthehabitatsofmanyplantsandanimals.

Cuttingdownforestsandpollutingriversdestroysthehabitatsofmanyformsoflife.

Thereisnolongeranydoubtthatthisishappening

Speciesoflifearedisappearingatanincreasingrate.

Globaltemperaturesarerisingandweatherpatternsarechanging.

Scientistsarewarningusthatfastactionisnecessarytosaveourfuture.

Ifwedon'tact,wemaygothewayofthedinosaurs.

（Thisnewextinctioneventiscausedbyhumans.）

Level4Unit2Part1Vocabulary-BodySystems

Thebody'scirculatorysystemincludestheheartandbloodvessels.

Theheartpumpsbloodtoallpartsofthebodythroughanetworkofarteriesandveins.

Thedigestivesystembreaksdownandabsorbsfoodintothebody.

Itsuppliestheenergythatthebodyneedsforgrowthandrepair.

Afterdigestion,excessfoodisturnedintowasteandeliminatedfromthebody.

Thenervoussystemincludesthebrain,spinalcordandnerves.

Thisisyourbody'scontrolsystem.

Itcontrolsyour musclesandorgans,includingyourcirculatoryanddigestivesystems.

Therespiratorysystemincludesthenoseandlungs.

Itbringsairandoxygenintothebodyandremovescarbondioxide.

Thelungsarewhereoxygenentersthebloodstreamandcarbondioxideisremoved.

Theimmunesystemprotectsthebodyagainstinfectionsanddiseases.

Sneezingandfeverareexamplesofhowtheimmunesystemworks.

Ifaninfectioninvadesthebody,theimmunesystemattacksit.

（Thebloodvesselsthatcarryoxygen-richblood from theheartarecalledarteries.）

（Thedigestivesystemiswherefoodisbrokendownandabsorbedintothebody.）

（Thenervoussystemregulatesyourheartbeatanddigestion.）

Level4Unit2Part1Vocabulary-GreatDiscoveries

Thecontrolleduseoffireallowedpeopletocookfoodandsurviveinthecolderclimates.

Fireprovidedlightsothatpeoplecouldworkand socialize forlongerhours.

Withtheinventionof agriculture,peoplecouldgrowfoodand settleintocommunities.

Bygrowingfood,peoplecouldspendlesstimehuntingandmoretimeforotherthingssuchasart.

The domestication ofanimalsallowedpeopletoraiseanduseanimalsforfoodandwork.

Byraisingherdsofanimalssuchassheep,humanshadaregularsupplyofmeatandclothing.

Thestrengthofanimalssuchashorsesand oxen wasusedforworkandtransportation.

Thedevelopmentof toolsandmachineshasresultedinmoreefficient manufacturingandconstruction.

Withbettertoolsandmachines,workcanbedonewithfewerpeopleandatmuchlowercosts.

Thedevelopmentofscienceandengineeringhasimprovedmanythings,includingcommunications.

Withanunderstandingofelectricity,telephonesandradiosallowpeopletocommunicateoverlongdistances.

（Scienceandengineeringhavechangedthewaywecommunicatewitheachother.）

（Withthedevelopmentofagriculture,peoplehadmoretimeforotheractivities.）

（Theuseofmachineshasreducedthenumberofpeopleneededtomakethings.）

Level4Unit2Part1Dialogue-SmartphoneAddiction

Itookavacationlastnight.

Whatareyoutalkingabout?

Wheredidyoutakeyourvacation?

Ididn'tgoanywhere.

Ijustspentaneveningwithoutmysmartphone.

Howwasit?

Itwasgreat.Igotarealmagazineandreaditwithnointerruption.

Itwasverypeaceful.

Yes,Ihaven'tdonethatinalongtime.

Youknowwhat?

I'mbeginningtohatesmartphones.

Really?

butyoucan'tlivewithoutone,right?

Yes,that'stheproblem.

Thesethingsarechangingthewaypeoplelive.

Yes,Ijustsawadocumentaryaboutthat.

Ahusbandwascomplainingtohiswifethatshewasspendingtoomuchtimeonhersmartphone.

Whathappened?

Didtheygetadivorce?

Youguessedit.Intheend,theygotadivorce.

It'sabitironic,don'tyouthink?

Smartphoneweresupposedtobringpeopletogether,buttheyarepullingpeopleapart.

Yes,youareright.

Hey,justaminute.I'vegotamessageonmysmartphone,anditcan'twait.

Level4Unit2Part1Dialogue-RudeBoss

Hey,wakeupandgetbacktowork.

What'swrongwithyou?

I'monmybreaksir,andIhaveabadheadache.

Well,wearenotpayingyoutosleep.

Ifyou'regoingtosleep,sleepsomeplaceelse.

Yes,sir,sorry,itwon'thappenagain.

Ithadbetternot.

Justaminute.

Don'ttalktomelikethat.

Whatdidyousay?

Youhurtme.youdon'thavetotreatpeoplelikethat.

Well,ifyoudon'tlikeit,Isuggestyouleave.

OK,Iwill.I'vehadenoughofyou.

I'llgetajobsomewhereelse.

（Themanagertreatstheemployeesinathreateningmanner.）

（Theemployeetreatsthemanagerrespectfully.）

Level4Unit2Part2Listening-PointofView1

Thismanisholdingapieceoffruitinhishand.

Thepieceoffruitiseitheranorangeoranapple.

Wecan’tseewhichitisbecausewecan’tseeinsidethebox.

Theprobabilitythatitisanorangeisequaltotheprobabilitythatitisanapple.

Itmaybeanapple,anditmaybeanorange.

It’sgottobeoneortheother.

Itcan’tbeanythingelse.

Nowlet’slookatitfromtheman’spointofview.

Fromhispointofview,theprobabilitiesaredifferent.

Fromhispointofview,theprobabilitythathehasanorangeis100%or0%.

That’sbecauseheknowswhathehas.

Forhimthereisnouncertainty.

Ifhehasanorange,theprobabilityis100%.

Ifhedoesn’thaveanorange,theprobabilityis0%.

Heeitherhasitorhedoesn’t.

Fromourpointofview,theprobabilitythathehasanorangeis50%.

Fromhispointofview,theprobabilitythathehasanorangeis100%or0%.

Sotheprobabilitydependsonyourpointofview.

Level4Unit2Part2Listening-PointofView2

Peopleseethingsfromdifferentpointsofview.

Thisoftenleadstoargumentsbetweenpeople.

Herearesomeexamples.

Fromthisman’spointofview,heisrelaxing.

Heneedstorelaxbecausehehasbeenworkingtoohard.

Hehasn’tbeengettingenoughsleep.

Hiswifeseesthingsdifferently.

Sheisn’tawareofhowhardhehasbeenworking.

Fromherpointofview,heisdoingnothing.

However,sheknowswhatneedstobedonearoundthehouse.

Itisn’tfairthatshehastoworkwhilehedoesnothing.

Whenpeopleseethingsfromdifferentpointsofview,theyoftencometodifferentconclusions.

Thesedifferencescancauserealcommunicationproblems.

Level4Unit2Part2Vocabulary–Disasters

EarthquakesarecausedbyforcesdeepwithintheEarth.

Whentheearthshakes,buildingscancollapseandpeoplecanbeburiedinside.

Anexplosionisarapid,violentreleaseofenergy.

Explosionscanbecausedbychemicalreactions,suchasinsideanengine.

Asparkcanigniteamixtureofgases,andreleaseenergyforgoodordestructivepurposes.

Accidentsareoftencausedbypeopledoingfoolishthingsorbynotbeingcareful.

Onemajorcauseofaccidentsisdrivingtoofast.

Accidentswithfirecanbeveryserious,andcanresultinverypainfulinjuries.

Epidemicsaretherapidspreadofadisease,suchasthefluorebola.

Throughouthist