懂你英语L4U2.docx

懂你英语L4U2.docx

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懂你英语L4U2

懂你英语L4-Unit21ExtinctionEvents

Level4Unit21Listening 

ExtinctionEvents

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.

Scientistsestimatethattherehavebeenatleast5massextinctionsinthelast540millionyears.Theyalsobelievethatwehaveenteredanewextinctionevent.Speciesarebecomingextinctatamuchfasterratethanbefore.Insteadofasteroidsorvolcaniceruptions,thecurrenteventistheresultofhumanactivities.Humanactivities,forexample,haveledtoglobalwarming.

Globalwarmingistheresultofanincreaseincarbongasesinouratmosphere.Thesegasestrapheatfromthesun,sotheEarthisgettingwarmer.Asaresult,sealevelsarerisingandweatherpatternsarechanging.Inaddition,wehumansaredestroyingthehabitatsofmanyplantsandanimals.Cuttingdownforestsandpollutingriversdestroysthehabitatsofmanyformsoflife.

Thereisnolongeranydoubtthatthisishappening.Speciesoflifearedisappearingatanincreasingrate.Globaltemperaturesarerisingandweatherpatternsarechanging.Scientistsarewarningusthatfastactionisnecessarytosaveourfuture.Ifwedon'tact,wemaygothewayofthedinosaurs.（Thisnewextinctioneventiscausedbyhumans.）

Level4Unit21Vocabulary

BodySystems

Thebody'scirculatorysystemincludestheheartandbloodvessels.Theheartpumpsbloodtoallpartsofthebodythroughanetworkofarteriesandveins.（Thebloodvesselsthatcarryoxygen-richbloodfromtheheartarecalledarteries.）

Thedigestivesystembreaksdownandabsorbsfoodintothebody.It'ssuppliestheenergythatthebodyneedsforgrowthandrepair.Afterdigestion,excessfoodisturnedintowasteandeliminatedfromthebody.（Thedigestivesystemiswherefoodisbrokendownandabsorbedintothebody.）

Thenervoussystemincludesthebrain,spinalcordandnerves.Thisisyourbody'scontrolsystem.Itcontrolsyourmusclesandorgans,includingyourcirculatoryanddigestivesystem.（Thenervoussystemregulatesyourheartbeatanddigestion.）

Therespiratorysystemincludesthenoseandlungs.Itbringsairandoxygenintothebodyandremovescarbondioxide.Thelungsarewhereoxygenentersthebloodstream,andcarbondioxideisremoved.

Theimmunesystemprotectsthebodyagainstinfectionsanddiseases.Sneezingandfeverareexamplesofhowtheimmunesystemworks.Ifaninfectioninvadesthebody,theimmunesystemattacksit.

GreatDiscoveries

Thecontrolleduseoffireallowedpeopletocookfoodandsurviveinthecolderclimates.Fireprovidedlightsothatpeoplecouldworkandsocializeforlongerhours.

Withtheinventionofagriculture,peoplecouldgrowfoodandsettleintocommunities.Bygrowingfood,peoplecouldspendlesstimehunting,andmoretimeforotherthingssuchasart.（Withthedevelopmentofagriculture,peoplehadmoretimeforotheractivities.）

Thedomesticationofanimalsallowedpeopletoraiseanduseanimalsforfoodandwork.Byraisingherdsofanimalssuchassheep,humanshadaregularsupplyofmeatandclothing.Thestrengthofanimalssuchashorsesandoxenwasusedforworkandtransportation.

Thedevelopmentoftoolsandmachineshasresultedinmoreefficient manufacturingandconstruction.Withbettertoolsandmachines,workcanbedonewithfewerpeopleandatmuchlowercosts.（Theuseofmachineshasreducedthenumberofpeopleneededtomakethings.）

Thedevelopmentofscienceandengineeringhasimprovedmanythings,includingcommunications.Withanunderstandingofelectricity,telephonesandradiosallowpeopletocommunicateoverlongdistances.（Scienceandengineeringhavechangedthewaywecommunicatewitheachother.）

Level4Unit2Part1Dialogue

SmartphoneAddiction

Itookavacationlastnight.

Whatareyoutalkingabout?

Wheredidyoutakeyourvacation?

Ididn'tgoanywhere.

Ijustspendaneveningwithoutmysmartphone.

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.

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.）

懂你英语L4-Unit22 Point of view

Level4Unit2Part2Listening

Pointofview

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.

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.Explosionscanbecausedbychemicalreaction,suchasinsideanengine.Asparkcanigniteamixtureofgases,andreleaseenergyforgoodordestructivepurposes.

Accidentsareoftencausedbypeopledoingfoolishthingsorbynotbeingcareful.Onemajorcauseofaccidentsisdrivingtoofast.Accidentswithfirecanbeveryseriousandcanresultinverypainfulinjuries.

Epidemicsaretherapidspreadofadisease,suchasthefluorEbola.Throughouthistoryepidemicshavekilledmillionsofpeople.

Stormsarecausedbychangesintheatmosphereresultinginhighwindsandheavyrain.Thunderstormsarecausedbyelectricchargesintheatmospherethatproducelightning,whichcancauseforestfires.Some