TPO托福阅读真题答案及解析

托福阅读真题答案及解析TPOTPO是我们常用的托福模考工具，对我们的备考很有价值，下面我给大家带来TPO托福阅读真题答案及解析TPO托福阅读真题答案及解析托福阅读真题The Long-Term Stabilityof EcosystemsPlant communities assemblethemselves flexibly,andtheir particular structure depends on thespecific historyof the area.Ecologists usethe term“succession”to referto the changes that happen in plant communities andecosystemsover time.The firstcommunity in a succession is called apioneer community,while thelong-lived communityat theendof succession is calleda climax community.Pioneer andsuccessional plantcommunities are saidto changeoverperiods from1to500years.These changes一in plantnumbersand the mix of species一are cumulative.Climax communitiesthemselves change butover periodsof timegreater than about500years.An ecologistwho studiesa pondtoday maywell find itrelatively unchangedin ayear stime.Individual likewisesuggest that diversity does not guarantee ecosystem stability一just theopposite,in fact.A morecomplicated systemis,in general,more likelythan asimple systemto break down.A fifteen-speed racingbicycle ismore likelyto breakdownthan achild stricycle.

7.Which of the followingcan beinferred fromparagraph5about redwoodforestsOThey becomeless stableas theymature.OThey supportmany specieswhen theyreach climax.OThey arefound in temperate zones.O Theyhave reduceddiversity duringmid-successionalstages.

8.The word“guarantee“in the passage isclosest inmeaningtoOIncreaseOEnsureOFavorOComplicate

9.In paragraph5,why doesthe authorprovide theinformationthat A fifteen-speed racingbicycle ismorelikely to breakdownthan achild stricycle”O Toillustrate ageneral principleabout the stabilityof systemsby usingan everydayexampleO Todemonstrate thatan understandingof stabilityinecosystems can be appliedto helpunderstand stabilityinother situationsOTomake acomparison thatsupports theclaim that,ingeneral,stability increaseswith diversityOTo providean examplethat contradictsmathematicalmodels of ecosystemsParagraph6:Ecologists areespecially interestedtoknow whatfactors contributeto theresilience ofcommunitiesbecause climax communities allover theworld arebeingseverely damagedor destroyedby humanactivities.Thedestruction causedby thevolcanic explosionof MountSt.Helens,in thenorthwestern United States,for example,palesin comparisonto thedestruction causedby humans.We needto know whataspects ofa communityare mostimportant to thecommunity^s resistance to destruction,as wellas itsrecovery.

10.The word“pales”in the passage isclosestin meaningtoOIncreases proportionallyODiffersOLoses significanceOIscommonParagraph7Many ecologistsnow think that therelativelong-term stability of climax communities comes not fromdiversitybut from the“patchiness”of the environment,anenvironment thatvaries from place to place supportsmorekinds of organisms thanan environmentthat isuniform.Alocal populationthat goesextinct isquickly replacedbyimmigrants froman adjacentcommunity.Even ifthe newpopulationis ofa differentspecies,it canapproximatelyfill theniche vacatedby theextinct populationand keepthefood webintact.

11.Which of the sentencesbelow bestexpresses theessentialinformation in the highlightedsentence in thepassage Incurredchoices changethe meaningin importantwaysor leaveout essentialinformation.OEcologists now thinkthat thestability of anenvironmentis aresult ofdiversity ratherthan patchiness.OPatchy environmentsthat varyfromplace toplacedo notoftenhave highspecies diversity.O Uniformenvironments cannotbe climaxcommunitiesbecause theydo notsupport asmany types oforganismsaspatchy environments.O Apatchy environmentis thoughtto increasestabilitybecause itis ableto supporta widevariety oforganisms.

12.The word“adjacent“in the passage isclosest inmeaningtoOForeignOStableOFluidONeighboringParagraph6:Ecologists areespecially interestedtoknow whatfactors contributeto theresilience ofcommunitiesbecause climaxcommunities allover theworld arebeingseverely damagedor destroyedby humanactivities.Thedestruction causedby thevolcanic explosionof MountSt.Helens,in thenorthwestern UnitedStates,for example,palesin comparisonto thedestruction causedby humans.We needto know whataspects ofa communityare mostimportant to thecommunity sresistance todestruction,as wellas itsrecovery.

13.Look at the foursquares[]that indicatewhere thefollowingsentence couldbe addedto thepassage.In fact,damage totheenvironmentby humansis oftenmuchmore severethan damageby naturalevents andprocesses.Where wouldthe sentencebest fitClick ona squaretoadd thesentence tothepassage.

14.Directions:An introductorysentence fora briefsummaryof thepassage isprovided below.Complete thesummaryby selectingthe THREEanswer choicesthat expressthe mostimportantideas in thepassage.Some sentencesdo notbelongin thesummary because they expressideas thatare notpresentedinthepassage orare minorideas inthepassage.This questionis worth2points.The processof successionand thestabilityofa climaxcommunitycan changeover time.Answer choicesOThechanges thatoccur in an ecosystemfrom thepioneerto the climaxcommunitycan beseen inone humangeneration.O Ahigh degreeof species diversity does not alwaysresultinastable ecosystem.O Thelevel ofresilience ina plantcommunitycontributes toits long-term stability.OEcologists agreethat climaxcommunitiesarethe moststabletypesof ecosystems.O Disagreementsover themeaning ofthe term“stability”make itdifficult toidentify the most stableecosystems.OThe resilience of climaxcommunities makesthemresistant todestruction causedby humans.托福阅读真题参考答案

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0214.0235托福阅读真题译文生态系统的长期稳定植物群体可以自由地聚集，他们特殊的结构取决于聚集区域的具体历史生态学家使用“演替”来诠释植物群落和生态系统随着时间推移所发生的变化演替中的第一个群落被称作先锋群落，而处于演替最后那个长期生存的群落被称为顶极群落先锋群落和紧接着的植物群落的变化周期是从1到500年不等，植物数量和混合种类数量的变化是慢慢积累的顶极群落本身也改变，但其变化周期超过500年现代一个研究池塘的生态学会发现池塘在一年当中相对而言是不变的个别鱼类可能被替换，但一年一年鱼的总数都趋于一致也就是说，生态系统自身的性质比组成生态系统的单个生物体更为稳定生态学家们一度认为物种的多样性使生态系统稳定，生态系统物种越多样则生态系统越稳定通过观察得出的结论支持了这个观点，长期持久的顶极群落通常要比先锋群落具备更为复杂的食物网和更多的物种生态学家家们得出的结论是顶点生态系统的稳定性明显取决于他们的复杂化程度举个极端的例子，在单一作物的农田中，一年的恶劣天气或单一害虫的入侵就可以摧毁所有作物与此相反，在一个复杂的顶极群落里，如温带森林，他们便可以抵御来自气候和害虫的入侵不管怎样，生态系统稳定性的问题非常复杂首先，不是所有的生态学家都赞同“稳定”的含义稳定性可以简单地定义为缺乏变化如果是这样的话，顶极群落将被视为最稳定的，因为根据定义，他们随着时间推移而变化是最少另外，稳定性也可以界定为生态系统在经历了严重破坏之后回复原貌的速度，比如火灾这种稳定性也被称作弹性在这种情况下，顶极群落将是最脆弱和最不稳定的，因为他们可能需要数百年时间才能恢复到顶点状态即使是这种被定义为简单地缺乏变化的稳定性并非总是与最多样的物种联系起来至少在温带地区，会经常在演替过程中发现最多物种，而不是在顶极群落中例如，红树林一旦成熟，其中的物种数量以及单个物种的数量都会减少总的来说，多样性本身并不能保证稳定性，生态系统的数学模型也可以得出同样的结论一般来说，一个更复杂的系统可能比一个简单的系统更容易被破坏（一个十五速的（赛车）比一个孩子的三轮车更容易损坏）生态学家们更想弄清楚到底哪些因素有助于促成群落的恢复，因为世界各地的顶极群落都因为人类活动而遭受到严重的损坏或毁坏就像美国西北部圣海伦火山的猛烈喷发所造成的破坏，在人类活动对环境造成的的破坏面前也相形见细我们必须了解对群落抵抗破坏和恢复来说哪些是最重要的现在的很多生态学家们认为，顶极群落相对长期的稳定性并非来于自多样性，而是来自环境的“补缀”，随处变化的环境比统一的环境更有利于多种有机体的生存当地物种灭亡后，马上就会被相邻群落的移民取代即便是另一种不同的物种，他们也可以填补那些已灭绝生物的空缺，并保持食物网的完整TPO托福阅读真题答案及解析相关（文章）★2021年1月托福阅读真题回忆及解析★TPO53托福阅读Passage3题目及答案解析★托福TPO1阅读真题原文及答案翻译part3★TPO53托福阅读Passagel原文及答案解析★托福TPO3阅读真题原文及答案翻译Part3★托福TPO5阅读真题文本翻译及答案Parti★TPO53托福阅读Passage2原文及答案解析★托福TPO1阅读文本及题目答案Parti★托福TP03阅读真题原文题目及答案Part2fish may be replaced,but the number offish willtend to bethe samefrom oneyear tothe next.We cansay that theproperties of an ecosystemare morestable thanthe individualorganismsthat composethe ecosystem.At onetime,ecologists believedthat speciesdiversitymade ecosystemsstable.They believedthat thegreater thediversitythe morestable the ecosystem.Support forthis ideacame fromthe observation thatlong-lasting climaxcommunities usually have more complexfood websand morespeciesdiversity than pioneer communities.Ecologistsconcluded that the apparent stabilityof climax ecosystemsdepended on their complexity.To takean extremeexample,farmlands dominatedby a single cropare sounstable thatoneyear ofbad weatheror theinvasion ofa singlepest candestroythe entirecrop.In contrast,a complexclimaxcommunity,such asa temperateforest,will tolerateconsiderabledamage fromweather topests.The questionof ecosystemstability iscomplicated,however.The firstproblem isthat ecologistsdo not all agreewhat“stability”means.Stability canbe definedas simplylackof change.In thatcase,the climaxcommunity would beconsidered the most stable,since,by definition,it changesthe least over time.Alternatively,stability canbe definedas the speed with which an ecosystemreturns toa particularform following a major disturbance,such asa fire.This kindof stability is also calledresilience.In thatcase,climaxcommunities would be themost fragileand the least stable,since theycan requirehundreds ofyears to return totheclimax state.Even thekind ofstability definedas simplelack ofchangeis not always associatedwith maximum diversity.Atleast intemperate zones,maximum diversityis oftenfoundin mid-successional stages,not inthe climaxcommunity.Oncea redwoodforest matures,for example,the kindsof speciesand the number of individualsgrowing onthe forestfloor arereduced.In general,diversity,by itself,does notensurestability.Mathematical modelsof ecosystemslikewisesuggestthatdiversitydoes notguaranteeecosystemstability一just theopposite,in fact.A morecomplicated systemis,in general,more likelythanasimple systemto breakdown.Afifteen-speed racingbicycle ismore likelytobreakdownthan achild stricycle.Ecologists areespecially interestedtoknowwhatfactors contributetotheresilienceofcommunities becauseclimaxcommunities allover theworld arebeing severelydamagedor destroyedby humanactivities.The destructioncausedby thevolcanic explosionof MountSt.Helens,in thenorthwesternUnitedStates,for example,pales incomparisonto thedestruction causedby humans.We needtoknowwhataspects ofa communityare mostimportant tothe communitysresistancetodestruction,as wellas itsrecovery.Many ecologistsnowthinkthattherelative long-termstability ofclimaxcommunitiescomesnotfrom diversitybutfrom the“patchiness“oftheenvironment,an environmentthatvaries fromplacetoplace supportsmore kindsoforganisms thanan environmentthat isuniform.A localpopulationthat goesextinct isquickly replacedbyimmigrants froman adjacentcommunity.Even ifthe newpopulationis ofa differentspecies,it canapproximatelyfill theniche vacatedby theextinct populationand keepthefood webintact.Paragraph1:Plantcommunitiesassemble themselvesflexibly,and theirparticularstructuredependsonthespecific historyofthearea.Ecologists usethe term“succession”to refertothechangesthathappenin plantcommunities andecosystems over time.The firstcommunity ina successioniscalledapioneer community,while thelong-lived communityattheend ofsuccessioniscalled aclimaxcommunity.Pioneer andsuccessionalplantcommunitiesare saidto changeover periodsfrom1to500years.Thesechanges一inplantnumbers andthe mixofspecies一arecumulative.Climax communitiesthemselveschangebut overperiodsof timegreater thanabout500years.TPO托福阅读题目

1.The word“particular“inthepassage isclosest inmeaningtoONaturalOFinalOSpecif icOComplex

2.According toparagraph1,which ofthe followingisNOT trueofclimax communitiesOThey occurattheend ofasuccession.OThey lastlonger thanany othertype ofcommunity.O Thenumbers ofplants inthem andthemixof speciesdonot change.OThey remainstable forat least500years ata time.Paragraph2:An ecologistwho studiesa pondtoday maywellfinditrelatively unchangedinayear stime.Individual fishmaybereplaced,but thenumberoffish willtendtobethe samefrom oneyear tothe next.We cansay thattheproperties ofan ecosystemare morestable thantheindividual organismsthat composetheecosystem.

3.According toparagraph2,which ofthe followingprinciplesof ecosystemscanbelearned bystudying apondO Ecosystemproperties changemore slowlythanindividuals inthe system.OThe stabilityofanecosystem tendsto changeasindividuals arereplaced.Olndividual organismsare stablefrom oneyear tothenext.OA changeinthemembers ofan organismdoesnotaffectan ecosystems propertiesParagraph3:At onetime,ecologists believedthatspecies diversitymade ecosystemsstable.They believedthatthe greaterthe diversitythe morestable theecosystem.Support forthis ideacamefromtheobservationthatlong-lasting climaxcommunitiesusuallyhavemorecomplexfood websand morespeciesdiversitythanpioneer communities.Ecologists concludedthattheapparentstabilityof climaxecosystemsdependedontheircomplexity.To takean extremeexample,farmlands dominatedby asingle cropare sounstablethat oneyear ofbad weatheror theinvasion ofasinglepestcan destroythe entirecrop.In contrast,a complexclimaxcommunity,such asa temperateforest,will tolerateconsiderabledamage fromweather ofpests.

4.According toparagraph3,ecologists oncebelievedthat which ofthe following illustratedthemost stableecosystemsOPioneer communitiesOClimaxcommunitiesOSingle-crop farmlandsOSuccessionalplant communitiesParagraph4:The questionofecosystemstability iscomplicated,however.The firstproblem isthat ecologistsdonotallagree what“stability“means.Stability canbedefined assimply lackof change.In thatcase,the climaxcommunitywouldbe considered themoststable,since,bydefinition,it changestheleastovertime.Alternatively,stability canbe definedasthespeedwithwhichanecosystemreturns toa particularformfollowingamajordisturbance,such asa fire.This kind ofstabilityisalsocalledresilience.In thatcase,climaxcommunitieswouldbethe mostfragileandtheleast stable,since theycan requirehundredsof yearstoreturntotheclimax state.

5.According toparagraph4,why isthe questionofecosystem stabilitycomplicatedOThe reasonsfor ecosystemchange arenotalwaysclear.OEcologists oftenconfuse the word“stability”with theword^resilience.”OThe exactmeaning oftheword“stability”is debatedbyecologists.OThere aremany differentanswers toecologicalquestions.

6.According toparagraph4,whichofthefollowingistrue ofclimaxcommunitiesOThey are moreresilient thanpioneercommunities.OThey canbeconsideredboth themost andthe leaststablecommunities.O Theyare stablebecausetheyrecover quicklyaftermajor disturbances.OTheyarethemostresilient communitiesbecause theychangetheleastovertime.Paragraph5:Even thekindofstability definedas simplelackof changeis notalways associatedwith maximumdiversity.At leastintemperatezones,maximumdiversityis oftenfoundin mid-successional stages,not intheclimaxcommunity.Oncea redwoodforest matures,for example,the kindsof speciesandthenumberof individualsgrowing onthe forestfloor arereduced.In general,diversity,by itself,doesnotensurestability.Mathematical modelsofecosystems。