Unit+5+A+delicate+World+Starting+out+ Understanding+ideas+课件【知识精讲精研】高二英语外研版（2019）选择性必修第二册

Unit5Period1Startingout&Understandingideas课堂学习Watchthevideoandanswerthequestions.1ArehumanspartofEarth'secosystems?Why?2Inwhatwayscanhumansaffectecosystems?1Startingout1ArehumanspartofEarth'secosystems?Why?2Inwhatwayscanhumansaffectecosystems?Yes.HumansarepartofEarth'secosystems.Becauseallthelivingthingsliveinecosystemsandpeoplearelivingthings.Humanscanaffectecosystemsinpositiveandnegativeways.Forexample,tohaveapositiveinfluenceonecosystems,peoplecanplanttrees,feedandprotectanimals,recyclethings,etc.However,deforestation,airandwaterpollutionandexcessivewasteaffectecosystemsinanegativeway.2Whatdoyouthinkalatersatelliteimagewouldshow?3Whatdoyouthinkcausedthesechanges?Lookatthesatelliteimagesandanswerthequestions.21Whatishappeningtotheareaaccordingtothesatelliteimages?AralSeaisbecomingsmallerandsmaller/shrinking.Thewaterareawillbesmaller.Maybeit'sduetooverexploitation.1Lookatthepictureandanswerthequestions.Understandingideas1Whatanimalscanyouseeinthepicture?2Whatkindofchangeswouldtakeplace

ifcats,ratsandrabbitswereintroduced

toanenvironmentlikethis?Penguinsandabird.Theywouldhuntthebirdsandeatthenativevegetation,thusupsettingthelocalecologicalbalance.MACQUARIEISLAND:fromChaostoConservation1

IamstandingonMacquarieIsland,intheSouth-westPacificOcean,halfwaybetweenAustraliaandAntarctica.Strongwindsandstormyseashavehelpedsculptitslong,thinshape.Thegreengrassandbarerockofitslandscapecontrastdramatically,givingitawildandnaturalbeauty.NovisitorwouldthinkitsurprisingthattheislandisaUNESCOWorldHeritageSite.Norwouldtheyfailtoimaginehowitsnativeinhabitants,includingroyalpenguins,kingpenguins,andelephantseals,existedinperfectharmonywiththeirnaturalhabitatforthousandsofyears.2

Buttheisland'smorerecenthistorytellsadifferentstory.It'satragicstorythatbeganin1810whenhumansarrivedontheisland.Intheirshipstheyunknowinglybroughtratsandmice.Thesesmallanimalsquicklytookovertheisland,eatingthebirds'eggsandattackingbabybirds.Catswerebroughttotheislandtocontroltheratsandmice.Unfortunately,thecatssubsequentlydevelopedanappetiteforthebirds,too.3Meanwhile,rabbitswereintroducedtotheislandasasourceoffoodforhumans.Looseontheisland,theydidwhatrabbitsdobest-theymultipliedrapidlyandbeganeatingthenativevegetationanddiggingholes,whichcausedsoilerosion.Theexplodingrabbitpopulationprovidedplentifulfoodforthecats,meaningthatthenumberofcatsalsoincreased.Thisinturnledtomorecatshuntingthebirds.Theendresultwasthatparakeets,oncelargeinnumberandnativetotheisland,diedoutin1891.4

EvenafterMacquarieIslandbecameanofficialnaturereserveinthe1970s,therabbitsremainedoutofcontrol.Expertsfeltitnecessarytocomeupwithaplantoremovealltherabbitsfromtheisland.Withthisgoalinmind,aviruswasreleasedontotheisland.Butalthoughtheviruscausedtherabbitpopulationtodecreasefrom130,000toaround10,000,italsomeantlessfoodforthecats.Thecatsinconsequenceturnedtheirattention-andtheirstomachs-backtothenativebirds,killingupto60,000eachyear.Inthe1980s,trapsanddogswereusedtocatchthecats.ThelastMacquarieIslandcatwascaughtin2000.5Butasthesayinggoes,“Whilethecat'saway,themicewillplay."Withthedepartureofthecatsfromtheisland,themouseandratpopulationstartedtoincrease.Andrememberthose10,000orsorabbits?Itturnedoutthattheydevelopedanimmunitytothevirus,andtheirnumbersexplodedonceagain.Then,in2006,therabbits'diggingcausedsomelandtocollapse,andkilledasubstantialnumberofpenguins.Thisincidentmadeitclearthattherat,mouseandrabbitproblemneededsolvingonceandforall.6

So,IamhereonMacquarieIslandtoparticipateintheprogrammetotacklethisveryproblem.Thefirststepinvolvedpoisonbeingdroppedfromhelicopters.Thenextstepistoremovethelastremaininginvadingspecies,andthat'swhereIcomein-withmydogs.Theyhavebeentrainedtofindeverylastone,withoutharmingthenativeanimals.Thisinterventionisalong,much-delayedendingtoasadstory,butwehumansoweittotheislandtogiveitahappyending.

Postscript:In2014,MacquarieIslandwasdeclaredpest-freeandtheisland'secologyisfinallyontheroadtorecovery.Non-nativespeciesintroducedtoMacquarieIslandattackednativebirds,andledtoasubstantialreductionofbirdpopulationandeventheextinctionofparakeets.Inaddition,non-nativespeciesateanddevastatedthenativevegetation.Allofthisplayedapartinupsettingthenaturalharmonyoftheisland.Butnowtheisland'secologyisontheroadtorecoverywithhumanefforts.Skimming2ReadthepassageandfindoutwhathappenedtoMacquarieIsland.Lookthroughthepassage,divideitintoparts,andgetthemainideaofeachpart.Part1Para.1ThelocationandnaturalcharacteristicsofMacquarieIslandPart2Para.2-Para.5ThetragedystoryofMacquarieIslandPart3Para.6WhattheauthorisdoingnowtoMacquarieIslandScanningChoosetheauthor'spurposeinwritingthepassageandgiveyourreasons.3Carefulreading1ToanalysehowMacquarieIslandwassavedfromdestruction.2ToinformreadersofthechaoscausedonMacquarieIslandbyhumans.3ToentertainreaderswithafunnystoryaboutwhathappenedonMacquarieIsland.4Tosuggestwaysinwhichanecosystemcanbeprotected.Organiseinformationfromthepassageandcompletetheflowchart.4Answers:ACTION(S)Catswerebroughttotheisland.Rabbitswereintroducedtotheisland.Aviruswasreleasedontotheisland.Trapsanddogswereused.Poisonanddogswereused.PURPOSE(S)Toprovidefoodforhumans.Toremovealltherabbitsfromtheisland.Tocatchthecats.Toremovealltheremaininginvadingspecies.→→→→RESULT(S)theytookovertheisland,eatingthebirds'eggsandattackingbabybirdsThecatsdevelopedanappetiteforthebirds.theexplodingrabbitpopulationprovidedplentifulfoodforthecats.Thisledtomorecatshuntingthebirds.Asaresult,parakeetsdiedoutin1891.Substantialreductionofrabbitpopulationledtocatskillingmorenativebirds.Thedepartureofthecatsresultedinanincreasingpopulationofratsandmice.Andtherabbitpopulationexplodedonceagain.Theislandwaspest-freeanditsecologyisontheroadtorecovery.→→→→→→NowtalkabouthowhumaninterferenceledtosuchsevereconsequencesforMacquarieIsland.1.In1810,humanarrivedontheisland.However,ratsandmicewerebroughttherebyaccident,andtheytookovertheisland,eatingthebirds’eggsandattackingbabybirds.2.Then,catswerebroughttotheisland.Butthecatsdevelopedanappetiteforthebirds.3.Rabbitswereintroducedtotheisland.Rabbitsmultipliedandcausedsoilerosion.Theexplodingrabbitpopulationprovidedfoodforthecats.Thisledtomorecatshuntingthebirds.Asaresult,parakeetsdiedoutin1891.4.Aviruswasreleasedontotheislandtoremovealltherabbitsfromtheisland.Substantialreductionofrabbitpopulationledtocatskillingmorenativebirds.5.Trapsanddogswerebroughttotheislandtocatchthecats.Thedepartureofcatsresultedinanincreasingpopulationofratsandmice.Andtherabbitpopulationexplodedonceagain.Then,in2006,therabbits'diggingcausedsomelandtocollapse,andkilledasubstantialnumberofpenguins.1Whatisyourunderstandingof“...wehumansoweittotheislandtogiveitahappyending”?2Doyouthinkitwasrighttoeradicatethe“pests”

fromMacquarieIsland?Giveyourreasons.3Howcouldsimilarsituationsbeavoidedinthefuture?4Whatlanguagecanyouusetotalkaboutcauseandeffect?Howwouldyouapplyittoyourreadingandwriting?Think&Share1Whatisyourunderstandingof“...wehumansoweittotheislandtogiveitahappyending”?2Doyouthinkitwasrighttoeradicatethe“pests”fromMacquarieIsland?Giveyourreasons.3Howcouldsimilarsituationsbeavoidedinthefuture?4Whatlanguagecanyouusetotalkaboutcauseandeffect?Howwouldyouapplyittoyourreadingandwriting?Yes.The“pests”inthesentencereferstotheinvadingspecies.Torestoretheecologicalbalance,itwasobviousthathumansmusteradicatethe“pests”.Itwashumansthatbroughtinvadingspeciestotheisland,breakingthebalanceoftheisland’snature.Soitisourdutytohelpitreturntonormal.Toavoidsimilarsituationsinthefuture,weshouldprotectthenaturalecosystemandbeawareofthepotentialimpactthathumanactivitiescanhaveonecosystems.1.MACQUARIEISLAND:fromChaostoConservation麦夸里岛：从混乱到保护

chaosn.[U]大混乱；紊乱causechaos导致混乱inchaos处于混乱之中economic/political/domesticchaos经济/政治/国内的混乱chaoticadj.混乱的；混沌的Languagepoints2.Thegreengrassandbarerockofitslandscapecontrastdramatically,

givingitawildandnaturalbeauty.

绿色的草地和光秃秃的岩石

景观形成了鲜明的对比，赋予了它一种野性和自然的美。

“giving...beauty”为现在分词短语作结果状语。3.NovisitorwouldthinkitsurprisingthattheislandisaUNESCOWorldHeritageSite.没有游客会对该岛被联合国教科文组织列为世界遗产感到惊讶。

本句为主从复合句。其中it作形式宾语，that引导宾语从句。4.Norwouldtheyfailtoimaginehowitsnativeinhabitants,includingroyalpenguins,kingpenguins,andelephantseals,existedinperfectharmonywiththeirnaturalhabitatforthousandsofyears.他们也不难想象出，数千年来，包括帝企鹅、王企鹅和象海豹在内的当地动物是如何与其自然栖息地完美地和谐共存的。

(1)nor为否定词，可以用在一个否定句之后来引出另一个相关的否定句，在这种情况下，它所引导的句子需要用倒装语序，常用结构为：

“nor+助动词/情态动词+主语+谓语动词+其他成分。

e.g.Hedidn'tquithisjob,norwashefired.

他没有辞职，也没有被解雇。

(2)failtodosth.意为“未能做成某事”，表示否定概念，

和否定词连用时表示肯定概念。

e.g.Thegreatbridgecannotfailtostopyouinyourtracks.

这座宏伟的大桥一定会让你止步观赏。拓展：failinsth./doingsth.做某事失败；没能做到某事

e.g.Hefailedinpersuadinghertogotherewithhim.

他没能说服她和自己一起去。

(3)how引导宾语从句，作imagine的宾语。5.It'satragicstorythatbeganin1810whenhumansarrivedontheisland.这个悲惨的故事始于1810年人类来到岛上。

本句中的It指的是前面的adifferentstory。that在此引导定语从句，修饰先行词atragicstory；该定语从句中包含一个when引导的定语从句，修饰1810，when在此定语从句中作时间状语。6.Thesesmallanimalsquicklytookovertheisland,eatingthebirds'eggsandattackingbabybirds.这些小动物很快占领了岛屿，吃鸟蛋并攻击幼鸟。此处的“eatingthebirds'eggs”和“attackingbabybirds”是and连接的两个并列的v.­ing短语，在句中作伴随状语。7.Catswerebroughttotheislandtocontroltheratsandmice.猫被带到岛上来控制老鼠。“tocontroltheratsandmice”为动词不定式短语作目的状语。8.Unfortunately,thecatssubsequentlydevelopedanappetiteforthebirds,too.不幸的是，这些猫后来也对这些鸟产生了食欲。

appetiten.[U·C,usuallysing]食欲，胃口[c]强烈欲望developanappetitefor...对……产生食欲haveagood/poor/noappetite胃口好/胃口不好/没有胃口haveanappetitefor...渴望……(appetite前可用形容词修饰)9.Meanwhile,rabbitswereintroducedtotheislandasasourceoffoodfor

humans.与此同时，兔子被引入岛上作为人类的食物来源。

introduce...to/into...把……引入……introduce...tosb.向某人介绍……introduceoneself自我介绍introductionn.介绍；引进；序言10.Looseontheisland,theydidwhatrabbitsdobest

-theymultipliedrapidlyandbeganeatingthenativevegetationanddiggingholes,whichcausedsoilerosion.放任其在岛上的情况下，它们做了兔子最擅长的事情——它们迅速繁殖，并开始吃当地的植被和挖洞，这导致了土壤侵蚀。what引导宾语从句；破折号后解释的是whatrabbitsdobest的内容。which引导非限制性定语从句，修饰整个主句。11.Theexplodingrabbitpopulationprovidedplentifulfoodforthecats,meaningthatthenumberofcatsalsoincreased.兔子数量的激增为猫提供了充足的食物，这意味着猫的数量也在增加。

“meaning...increased”为现在分词结构作结果状语；

that引导宾语从句。12.Thisinturnledtomorecatshuntingthebirds.这反过来又导致更多的猫捕猎这些鸟。

inturn反过来；继而，转而；轮流，依次

leadto导致；通向

e.g.Increasedproductionwill,inturn,leadtoincreasedprofits.增加生产会继而增加利润。13.Theendresultwasthatparakeets,oncelargeinnumberandnativetotheisland,diedoutin1891.最终的结果是，曾经数量庞大、原产于该岛的长尾小鹦鹉在1891年灭绝了。

(1)“thatparakeets....in1891”为that引导的表语从句。

(2)(be)nativeto原产自……e.g.TheseelephantsarenativetoAfrica.这些大象原产于非洲。

(3)dieout消亡；灭绝e.g.Howdidthedinosaursdieout?恐龙是如何灭绝的？14.EvenafterMacquarieIslandbecameanofficialnaturereserveinthe1970s,therabbitsremainedoutofcontrol.即使在20世纪70年代麦夸里岛成为官方自然保护区后，兔子仍然无法控制。(1)after引导时间状语从句。

(2)outofcontrol失去控制

e.g.Pricesarespirallingoutofcontrol.物价飞涨，失去控制。15.Expertsfeltitnecessarytocomeupwithaplantoremovealltherabbitsfromtheisland.

专家们认为有必要制定一个计划，把所有的兔子从岛上赶走。

“feltitnecessary”构成动词+it(“it”作形式宾语)+adj(作宾语补足语)，“tocomeupwithaplan”不定式短语为真正宾语后置；“toremovealltherabbitsfromtheisland”为不定式短语作后置定语，修饰aplan。16.Withthisgoalinmind,aviruswasreleasedontotheisland.怀着这个目标，一种病毒被释放到岛上。

此处属于with复合结构，介词短语inmind作宾补，该结构在句中作状语。17.Butalthoughtheviruscausedtherabbitpopulationtodecreasefrom130,000toaround10,000,italsomeantlessfoodforthecats.

但是，尽管病毒导致兔子数量从13万只下降到大约1万只，这也意味着猫的食物减少了。(1)although引导让步状语从句。

(2)

decreasev.（使）变小，（使）减少n.减少，减少的量decreaseby...减少了……（表示减少的量）decrease(from.…)to…(从……)减少到……（表示减少后的量）decreasein...在……方面减少adecreasein...在……方面减少onthedecrease在减少联想拓展：increasev.&n.增加，增长increaseto...增加到……（表示增加的结果）increaseby...增加了……（表示增加的幅度）increasein...在……方面增加ontheincrease在增加18.Thecatsinconsequenceturnedtheirattention-andtheirstomachs-backtothenativebirds,killingupto60,000eachyear.结果，这些猫把注意力——以及它们的胃——转移到了本土鸟类身上，每年杀死多达6万只鸟。

(1)inconsequence结果；因此

e.g.Inconsequence,retailsalesinArocaCityareboundtoincreasesubstantially.因此，ArocaCity的零售额必然会大幅增长。(2)“killing...year”为现在分词短语作结果状语。19.Inthe1980s,trapsanddogswereusedtocatchthecats.20世纪80年代，人们用陷阱和狗来抓猫。

trapn.夹子；陷阱；圈套；困境

vt.(trapped,trapped)困住；使陷入圈套betrappedin被困在……；陷入……中

=becaughtin=bestuckintrapsb.into(doing)sth.诱使某人做某事lay/setatrap(forsb./sth.)(给某人某物)设下圈套fall/walkintoatrap落入圈套20.Butasthesayinggoes,“Whilethecat'saway,themicewillplay."但正如俗语所说，“山中无老虎，猴子称大王”。

as引导非限制性定语从句。21.Andrememberthose10,000orsorabbits?

还记得那一万只左右的兔子吗？

orso大约，左右e.g.Wewanderedaboutthetownforanhourorso.我们在城里到处游逛了一个小时左右。22.Itturnedoutthattheydevelopedanimmunitytothevirus,andtheirnumbersexplodedonceagain.

事实证明，它们对病毒产生了免疫力，它们的数量再次激增。

(1)本句为主从复合句。其中It作形式主语，that引导主语从句。(2)turnout结果是，证明是；（大量）出席，参加；制造，生产turnout(tobe)...结果（是）……Itturnsoutthat...结果……23.Thisincidentmadeitclearthattherat,mouseandrabbitproblemneededsolvingonceandforall.这件事清楚地表明，老鼠和兔子的问题需要一劳永逸地解决。

(1)本句为主从复合句。其中it作形式宾语，th