【雷哥GMAT】GMAT文章层次划分方法.pdf

GMATGMAT 文章层次划分方法文章层次划分方法 之前说过支撑一篇文章的框架主要可以根据文章每段首句和每段段内转折词来找 那么 在找到框架之后又该怎么去划分框架下得细节内容 划分这些细节对于细节题的做题非常 有帮助 原则上我们主要根据具体情况下的句意来划分结构下的层次 比如有这么一段话 一 浙江有很多地方的人组成 绍兴人 温州人 宁波人 那么就可以根据这三类地方的人进行划分层次 问到宁波人的时候就只看宁波这第 3 层次就可以了 提高做题效率 另外一个例子是 一 人有不同部分组成 头部 上半身 下半身 脚 这个例子就根据具体情况 虽然是一个人为一个整体 但是文章下面分开部位进行介绍 那么这里就根据部位划分为 4 个层次 方便细节题回文定位 那么我们再以下面这篇文章为例 A A smallsmall numbernumber ofof thethe forestforest speciesspecies ofof lepidopteralepidoptera moths moths andand butterflies butterflies whichwhich existexist asas caterpillarsduringcaterpillarsduring mostmost ofof theirtheir lifelife cycle cycle exhibitexhibit regularlyregularly recurringrecurring patternspatterns ofof populationpopulation growthgrowth andand declinedecline suchsuch fluctuationsfluctuations inin populationpopulation areare knownknown asas populationpopulation cycles cycles Although Although manymany differentdifferent variablesvariables influenceinfluence populationpopulation levels levels a a regularregular patternpattern suchsuch asas a a populationpopulation cyclecycle seemsseems toto implyimply a a dominant dominant drivingdriving force force Identification Identification ofof thatthat drivingdriving force force however however hashas provedproved surprisinglysurprisingly elusiveelusive despitedespite considerableconsiderable research research The common approach of studying causes of population cycles by measuring the mortality caused by different agents such as predatory birds or parasites has been unproductive in the case of lepidoptera Moreover population ecologists attempts to alter cycles by changing the caterpillars habitat and by reducing caterpillar populations have not succeeded In short the evidence implies that these insect populations if not self regulating may at least be regulated by anan agentagent more intimately connected with the insect than are predatory birds or parasites RecentRecent workwork suggestssuggests thatthat thisthis agentagent maymay bebe a a virus virus For many years viral disease had been reported in declining populations of caterpillars but population ecologists had usually considered viral disease to have contributed to the decline once it was underway rather than to have initiated it The recent work has been made possible by new techniques of molecular biology that allow viral DNA to be detected at low concentrations in the environment Nuclear polyhedrosis viruses are hypothesized to be the driving force behind population cycles in lepidoptera in part because the viruses themselves follow an infectious cycle in which if protected from direct sun light they may remain virulent for many years in the environment embedded in durable crystals of polyhedrin protein Once ingested by a caterpillar the crystals dissolve releasing the virus to infect the insect s cells Late in the course of the infection millions of new virus particles are formed and enclosed in polyhedrin crystals These crystals reenter the environment after the insect dies and decomposes thus becoming available to infect other caterpillars OneOne ofof thethe attractionsattractions ofof thisthis hypothesishypothesis isis itsits broadbroad applicability applicability Remarkably despite significant differences in habitat and behavior many species of lepidoptera have population cycles of similar length between eight and eleven years Nuclear polyhedrosis viral infection is one factor these disparate species share 黑体字部分就是找出的结构 一 L 存在 population circle PC 二 PC 后面存在 driving force DF 三 identification of DF is hard 四 hypothesis may be Recent work this agent a virus 五 one of the attaction of the hypothesis broad appilicability 下面具体看黑体字剩下部分的细节层次划分 以第三四结构下细节划分为例 第三结构 IdentificationIdentification ofof thatthat drivingdriving force force however however hashas provedproved surprisinglysurprisingly elusiveelusive despitedespite considerableconsiderable research research The common approach of studying causes of population cycles by measuring the mortality caused by different agents such as predatory birds or parasites has been unproductive in the case of lepidoptera Moreover population ecologists attempts to alter cycles by changing the caterpillars habitat and by reducing caterpillar populations have not succeeded Inshort theevidenceimpliesthattheseinsectpopulations ifnot self regulating may at least be regulated by anan agentagent more intimately connected with the insect than are predatory birds or parasites 说找 driving force 是困难的 那么下面的细节展现了两点 1 是 common approach 不 行 2 是 population ecologists 的做法也不行 最后根据这 2 点提出了结论第 3 层次 因 为前面的找通常的 driving force 没成功 所以提出了 a more intimate angent 第四结构 RecentRecent workwork suggestssuggests thatthat thisthis agentagent maymay bebe a a virus virus For many years viral disease had been reported in declining populations of caterpillars but population ecologists had usually considered viral disease to have contributed to the decline once it was underway rather than to have initiated it The recent work has been made possible by new techniques of molecular biology that allow viral DNA to be detected at low concentrations in the environment Nuclear polyhedrosis viruses are hypothesized to be the driving force behind population cycles in lepidoptera in part because the viruses themselves follow an infectious cycle in which if protected from direct sun light they may remain virulent for many years in the environment embedded in durable crystals of polyhedrin protein Once ingested by a caterpillar the crystals dissolve releasing the virus to infect the insect s cells Late in the course of the infection millions of new virus particles are formed and enclosed in polyhedrin crystals These crystals reenter the environment after theinsectdiesanddecomposes thusbecomingavailabletoinfectother caterpillars 首先第四结构提出了猜想 recent work 提出 driving force 大概是 a virus 首先第 1 层次对猜想的对象 virus 进行了背景介绍 然后第 2 层次 recent work 提出 猜想的基础是有了一个 technique 第 3 层次说出了猜想的到底是哪种病毒 并说明了为什 么 NPV 第 4 层次 NPV 如何 infect 昆虫 比如说下面这题 45 According to the passage beforebefore thethe discoverydiscovery ofof newnew techniquestechniques for detecting viral DNA population ecologists believed that viralviral diseasesdiseases A were not widely prevalent among insect populations generally B affected only the caterpillar life stage of lepidoptera C were the driving force behind lepidoptera population cycles D attacked already declining caterpillar populations E infected birds and parasites that prey on various species of lepidoptera 关键词 viral diseases before the discovery of new techniques 那么可以定位 到第四结构第 1 层次 For many years viral disease had been reported in declining populations of caterpillars but population ecologists had usually considered viral disease to have contributed to the decline once it was underway rather than to have initiated it 说明以前认为 virus 是去影响已经在 decline 的 population 可以直接选 D 46 According to the passage nuclearnuclear polyhedrosispolyhedrosis virusesviruses cancan remainremain virulentvirulent in the environment only when A the polyhedrin protein crystals dissolve B caterpillar populations are in decline C they are present in large numbers D their concentration in a parti