1. It was possible to demonstrate by other methods refined structural differences among neuron types ; however , proof was lacking that the quality of the impulse or its condition was influenced by these differences , which seemed instead to influence the developmental patterning of the neural circuits .(5)  有可能通过其他方法来证明神经元种类间的细微的结构差异；可是，这样的证据是缺乏的，即神经冲动的性质或者状态是受这些差异所影响的，而这些差异看起来却能影响神经网络的发育模式。

难免类型：复杂修饰、倒装

解释：与很多人的印象相反，lack从来就不能作形容词，它只有动词或名词的词性。其形容词的形式是lacking,意思是缺乏的、不足的。

本句的在however 之前和之后的两个分句，是两个倒装结构，前一个是小倒装，正常语序是：to demonstrate refined structural differences among neuron types by other methods: however后面是个大倒装，lacking之后的that引导的同位语人名是修饰主语proof的，但是因为它太长，所以为了避免头重脚轻，被放到lacking之后，正常的语序应该是proof that the quality of ..was lacking

意群训练：

It was  possible  to demonstrate  by other methods  refined structural differences among neuron types; however,  proof was lacking  that the quality of the impulse  or its condition  was influenced by  these differences,  which seemed instead to influence  the developmental patterning  of the neural circuits.

2. Although qualitative variance among nerve energies was never rigidly disproved，the doctrine was generally abandoned in favor of the opposing view，namely，that nerve impulses are essentially homogeneous in quality and are transmitted as "common currency" throughout the nervous system. （4）尽管在神经能量上存在着质的不同，这一点从来都没有在严格的意义上被反对过，但是以上教条通常被抛弃掉，而转向相反的观点，即：神经冲动从根本上本质相同，而且被当作“一种普通流”在整个神经系统中传播。

难句类型：复杂修饰、双重否定

解释：前半个分句中有一个双重否定，was never rigidly disproved,这种表示法用中文说出来还是比较好懂的，原因是我们熟悉中文的这种表示法，但在英文中出现，因为在以前的学习中见得少，所以感觉上很别扭。因此，同学们的任务，就是通过反复阅读此类句子来熟悉这样的英语。其实在英文表达中，很多双重否定与中文表达是一样的，表示肯定；如not unlimited就等于limited。但是值得读者注意的是在GRE和GMAT这两种对考生的逻辑有苛刻要求的考试中，如果这种双重否定中所涉及的概念不是dichotomous(即二分法的词汇，比如上面例子中的limited和unlimited)，则双重否定不一定表示肯定；比如本例中的not disprove, 不能理解为agree，不反对者中，的确有人会同意，但通常心存疑虑，随大流者居多。不但如此，大双重否定中加上限定词以后，在否定的范围上也有所变化，如本句的be never rigidly disproved，没有完全被反对，不能理解为从来都被严格支持的，而应该理解成从来都可能有人支持的。综上所述，对双重否定的句子，简单的把其置换为肯定，不是最精确的理解。而最好的办法，就是通过多读、多练来熟悉其语言表达及其逻辑方式，按照其字面的表达理解成没有完全否定，然后大脑中反应出其目前的生存状态是一个仍未消失的状态；这种理解才是在考试现场既快速又精确的理解。

运用前面所说的用合理化原则中的取非读法，可以很容易的读出作者在后半个分句中想说前面的那种观点被反对了。但是，初学者会对这个分句中的something be abandoned in favor of something else这种语言表达感到突然，如果理解成因为喜后者而抛弃了前者，虽然也能说得通，但是其实原文从来没有这种因果关系，in favor of强调的是这两种动作的同时性；抛弃了前者，而转向后者，namely之后的内容是前面的opposing view的同位语。

意群训练：

Although qualitative variance  among nerve energies  was never rigidly disproved,  the doctrine  was generallyabandoned  in favor of  the oppsing view,  namely,  that nerve impulses are essentially homogeneous  in quality  and are transmitted  as "common currency" throught the nervous system

3. Other experiments revealed slight variations in the size，number，　　arrangement，and interconnection of the nerve cells，but as far as psycho neural correlations were concerned，the obvious similarities of these sensory fields to each other seemed much more remarkable than any of the minute differences. （4 -）尽管其他实验显示在神经细胞的大小、数量、排列和相互连接上有一些小的差异，但是就心理-神经的关系而言，这些感官区域彼此之间的明显的相似性看起来比起微小的差异更为令人注目。

难句类型：复杂修饰、插入语

解释：在前后两个分句之间有一个插入语as far as psychoneural correlations were concerned。在后面的分句中，主语the obvious similarities之后的、修饰主语的成分较长、以至于有很多读者看到相隔很远的more remarkable than时一下子反应不过来是什么比后者更明显。其简化形式应为：similarities seemed more remarkable than differences。

意群训练：

Other experiments revealed  slight variations  in the size, number, arrangement,  and interconnection  of the nerve cells,  but as far as psychoneural correlations  were concerned, the obvious similarities of  these sensory fileds  to each other  seemed much more  remarkable than  any of the  minute differences.

4. Although some experiments show that，as an object becomes familiar，its internal　representation becomes more holistic and　the recognition process correspondingly more parallel，the weight of evidence　seems to support the serial hypothesis，　　at least for objects that are not notably simple and familiar. （4+）
虽然某些实验表明，随着一个物体变得熟悉起来，其内心再现图像亦更具整体感，辨认过程相应地更趋于平行，但证据的砝码似乎在支持序列假设（serial hypothesis），至少是对于那些不甚简单、不甚熟悉的物体来说。

难句类型：复杂修饰、插入语、省略

解释：在Although引导的分句中，谓语shows后面跟着一个长长的宾语从句，从句中先出现一个插入语as an object becomes familiar,之后的内容是由and 连接的两套并列的主谓宾。其实and前后就是两个句子，只不过作者省略了后面的句子中与前面相同的引导词that和谓语become。

句子中有一个生词holistic，其实即使不认识，也能用合理化原则猜出它是后面serial的反义词、parallel的同义词，大约是统一、完整或同时的意思；其实只要能理解到其是与serial相反的意思即可。

意群训练：

Although some experimentsshow that，as an objectbecomes familiar，its internal　representationbecomes more holisticand　the recognition processcorrespondingly more parallel，the weight of evidence　seems to supportthe serial hypothesis，　　at least for objectsthat are notnotably simpleand familiar.

5. In large part as a consequence of　the feminist movement，historians have focused a great deal of attention in recent years on determining more accurately the status of women in　various periods. （3+）
在很大程度上，由于女权主义运动（feminist movement）的缘故，史学家近年来汇聚了大量的注意力，来更为准确地确定妇女在各个历史时期的地位。 Focus A on B;

难句类型：倒装

解释：focus A on B指把A集中于B，本句中介词on的宾语determining/more accurately the status of women invarious periods中有一个小倒装，正常语序应该是determining the status of women in various periods more accurately。

意群训练：

In large part  as a consequence of  the feminist movement,  historians have focused  a great deal of  attention  in recent years  on determining   more accurately the status of women in various periods.

6. If one begins by examining why ancients refer to Amazons , it becomes clear that ancient Greek descriptions of such societies were meant not so much to represent observed historical fact –real Amazonian societies – but rather to offer “moral lessons” on the supposed outcome of women’s rule in their own society . (4)  如果我们先研究一下为什么古人会提到亚马逊人，下面的一点就变得清晰了，那就是古希腊对于这种社会的庙睡不是太多的被用来表达观察的历史事实——真正的亚麻逊社会的——而是为了对于妇女在其社会中的统治的预期后果提供一种“道德教导”。

难句类型：复杂修饰、插入语、抽象词

解释：有两个词汇需要先解释一下：something be meant to represent是use something to mean的被动语态。mean在这里不是常用的"……的意思是"的意思，而是表示做某事所表达的目的、意图，其英文释义为：to serve or intend to convey, show, or indicate。句中的结构为：something be meant not so much to,,, but rather to, 实际上是把be meant to和not rather 的两个固定搭配套在一起，意思是：不是为了...而是为了...

另外，suppose的意思很抽象，不容易理解。此词既有据信、被认为的意思，也有预期的意思，还有表示贬义的假想的被想当然的意思。

本句的supposed用法极其特殊，在此处的意思，用以上任何一个释义来理解居然都可以成立，既是在说一个预期的社会状态，又是在说一个虚构出来的、本来不存在的社会状态，其用法类似于中文中的一语双关，是文章作者自以为文笔精妙之处。

意群训练：

If one begins  by examining why  ancients refer to Amazons,  it becomes clear that ancient Greek descriptions  of such societies  were meant  not so much  to represent  observed historical fact- real Amazonian societies- but rather to  offer"moral lessons"  on the supposed outcome  of women's rule  in their own society.

7. Thus，for instance，it may come as a shock to mathematicians to learn that the Schrodinger equation for the hydrogen atom is not a literally correct description of this atom，but only an approximation to a somewhat more correct equation taking account of spin，magnetic dipole，and relativistic effects；and that this corrected　equation is itself only an imperfect approximation to an infinite set of　quantum field-theoretical equations. （5）
因此，举例来说，对数学家而言，了解到下述情形可能会令其惊愕不已，即薛定谔（Schrodinger）的氢原子方程式并非是对该原子作出的一种绝然正确的描述，而仅仅是个近似值，趋近于一个在某种程度上更为正确的将自旋、磁性偶极子、以及相对论效应考虑在内的方程式；而这个得以纠正的方程式就其本身而言也只是一个不完美的近似值，趋近于无穷无尽的一整套量子场论方程式。

难句类型：复杂修饰、插入语、省略

解释：读到此句时，数学家不见得震惊，晕倒的考生恐怕不在少数。不但句子结构复杂，而且罗列了大量的专有名词。对于不是理科的同学来讲，在阅读这篇文章的现场清楚地明白应该读到什么程度远比研究这些生僻的专有名词更重要。其实是否知道薛定鄂方程对读者来说并不见得重要，GRE考试的出题者也不见得知道它；关键是要读懂句子的主要意思；数学家不能理解不精确和近似值的伟大意义。不过在本书中，出现的句子均以阅读训练为目的，所以读者仍要把句子的结构读清楚。

主句中的主语it是一个开工主语，其具体的内容应该是从to learn开始一直到句子结束的长达八行的不定式，但是此不定式实在太长，如果放在句首则句子无法平衡。Learn后面带着两个以that引导的宾语从句，中间以分号和and分开，可以把分号以后的句子看成是and it may come as a shock to mathematicians to learn that的省略形式。

意群训练：

Thus, for instance,  it may come  as a shock to  mathematiians to learn  that the Schrodinger equation for the hydrogen atom  is not a literally  correct description  of this atom,  but only  an approximation to  a somewhat more correct equation  taking account of  spin, magnetic dipole,  and relativistic effects; and that  this corrected equation  is itself  only an imperfect  approximation to  an infinite set of  quantum field-theoretical equations.

8. The physicist rightly dreads precise argument，since an argument that is　convincing only if it is precise loses all its force if the assumptions on　which it is based are slightly changed，whereas an argument that is convincing though imprecise may well be stable under small perturbations of its underlying assumptions. （5+）
物理学家恐惧于那些精确无误的论据不无道理，因为某种只有在它是精确无误的条件下才令人置信的论据，一旦它赖于建立其上的假设稍有变化，便会失去它一部的作用；而与此相反，一个尽管并不精确无误但却令人置信的论据，在其基本假设（underlying assumption）稍微受干扰的情况下，仍然有可能是站得住脚的。

难句类型：复杂修饰

解释：本句在文章中就是一个自然段，虽然长度比不上前面第一章中所举的那个长达10行的例子，但是难度绝不在那句话之下。本句堪称句子的大杂烩，连主句带从句居然一共有八个。从大往小说，由whereas连接了两个大句子，whereas后面的句子中的主语an augument之后又跟了一个定语从句that is convincing though imprecise，修饰augument。whereas前面共有六个句子，由the physicist作主语的主句；由since引导的原因状语从句，修饰since从句中主语an augument的由that引导的定语从句，此定语从句中的条件状语从句only if it is precise; since从句中的条件状语从句if the assumptions on which it is based are slightly changed,以及修饰此从句中的主语assumptions的定语从句on which it is based一共八个句子，从句套从句，实在令人叹为观止。

然而，在考试现场去数句子的数目，是只有呆子才会干的事，读者们惟一要干的事就是反复阅读这句话，什么时候练到不必去想其语法结构就能按原文顺序读懂，才算初步掌握；再进一步把它读顺，直到你看不出这个句子有什么特别的地方，看上去还挺舒服就算训练成功。

意群训练：

The physicist rightly  dreads precise argument,  since an argument  that is convincing only if it is precise loses all its force  if the assumptions  on which  it is based  are slightly changed,  whereas an argument  that is convincing though imprecise  may well be stable  under small perturbations  of its underlying assumptions.

9. However，as they gained cohesion，the Bluestockings came to regard themselves as a women’s group and to possess a sense of female solidarity lacking in the salonnieres，who remained isolated from one another by the primacy each held in her own salon. （4-）
起初，蓝袜女们确实模仿了法国沙龙女主人，将男性襄括到其小圈子中来。然则，随着她们获得的凝聚力，她们渐趋将自己视作一女性团体，并拥有了一种妇女团结意识，而这种意识在法国沙龙女主人身上则荡然无存，因为她们每个人在其自己的沙龙中自视甚高而彼此孤立隔绝开来。

难句类型：复杂修饰

解释：本句读到表示并列的连词and开始变难。and之后的不定式与前面的不定式是并列的，to的前面省略了一个与前面一样的谓语came。　lacking之后的分词作定语修饰a sense of female solidarity其后的由who引导的定语从句又修饰逗号前面的salonnieres此从句中又有一个定语从句that each salonniere held in her own salon修饰其前的primacy,但是由于引导词that在从句中作宾语，因此被省略。

意群训练：

However,  as they gained cohesion,  the Bluestocking  came to  regard themselves  as a women's group and to possess  a sense of female solidarity  lacking in the salonnieres,  who remained isolated  from one another  by the primacy  each held  in her own salon.

10. As my own studies have advanced，I have been increasingly impressed with the functional　　similarities between insect and vertebrate societies and less so with the structural differences that seem，at first glance，to constitute such an immense gulf between them. （5）
随着我的研究不断深入，我对昆虫和脊椎动物群落之间的功能类似性印象愈来愈深刻，而对结构上的差异印象愈发淡漠，虽然这些结构上的差异初看上去似乎构成了二者间一条无法愈越的鸿沟。

难句类型：复杂修饰、插入语、省略

解释：本句子的中间一段impressed with the functional similarites between insect and vertebrate societies and less so with the structural differences容易令人看晕，其中的insect and vertebrate societies and less so with由两个and连接了三个部分，然而它们其实不是同一层次的并列，第一个and实际上是between insect societies and vertebrate societies的一部分，是并列的，而and之后的less so with其实是对于一个完整的表达方式I have been increasingly less impressed with的省略形式，去掉了与前面重复的成分。

后面修饰的structural differences的定语从句that seem, at first glance, to constitute such an immense gulf between them中，又出现了一个别扭的插入语at first glance，把应该连在一起的seem to 粗暴地分开，令人不熟悉此类难句的人倍感不适。

意群训练：

As my own studies  have advanced,  I have been  increasingly impressed  with the  functional similarities between insect and  vertebrate societies  and less so with  the structural differences  that seem,  at first glance,  to constiture such an  immense gulf  between them.

11. Although fiction assuredly springs from political circumstances，its authors react to those circumstances in ways other than ideological，and talking about novels and stories primarily as instruments of ideology circumvents much of the fictional enterprise.（4）
虽然小说无疑起源于政治情状，但其作者则是以非意识形态的方式对这些政治情状作出反应的，而将小说和故事主要地当作意识形态的工具来探讨，会在相当程度上阻碍小说事业。

难句类型：复杂修饰

解释：本句从句子的结构上来讲，惟一的难度在于and之后的句子的主语talking about novels and stories primarily as instruments ofideology太长，以至于看到谓语circumvent的时候已经搞不清楚主谓了。更大的难度恐怕还在于对两个词汇的理解circumvent和enterprise。我们以前所背过的circumvent有两个词义，一个是规避，一是以计谋战胜，但是这两种意思放到此处都显然不通；其实circumvent有一个我们没有背过的最常用的意思是包围、限制或陷害；至于enterprise常用的意思是企业，这里的指事业。

意群训练：Although fictionassuredly springs frompolitical circumstances，its authors reactto those circumstancesin waysother than ideological，and talking aboutnovels and storiesprimarily as instruments of ideologycircumvents much ofthe fictional enterprise.

12. Is this a defect，or are the authors working out of，or trying to forge，a different kind of aesthetic？（3）
这究竟是一种缺陷呢，还是这些作者想要按照一种与众不同的美学体系进行创作，抑或是在试图创立一种与众不同的美学体系？

难句类型：插入语

解释：本句的句子既短，意思也不难理解，但插入语(or trying to forge)的干扰作用却极强。

意群训练：

Is this a defect,  or are the authors  working out of,  or trying to forge,  a different kind of  aesthetic?

13. In addition, the style of some Black novels, like Jean Toomer’s Cane, verges on expressionism or surrealism ; does this technique provide a counterpoint to the prevalent theme that portrays the fate against which Black heroes are pitted , a theme usually conveyed by more naturalistic modes of expression ? （5）

不仅如此，有些黑人小说（比如JT的甘蔗）的风格接近与表现主义和超现实主义；这种技巧是否为流行的主题提供了一个和谐的对应呢？这种主题刻画了黑人注意与之相抗争的命运，这是一个通常用更为自然主义的表现手法所表达的主题。

难句类型：复杂修饰、插入语

解释：在本句中有三个词需要先解释一番：verge on这个词组是接近于、濒于的意思，hero在文学作品中是主人公的意思，pit作动词时，除了挖坑、窖藏之外，还有使竞争、使斗争的意思，其英文释义为：to set as gamecocks into or as if into a pit to fight, to set into opposition or rivalry usually used with against.在此用的是后一种语义的被动语态fate againt which Black heros are pitted.如果用主动语态则是：pit black heros againt fate。

另外本句的结构复杂，分号之后是一个一般疑问句，但是由于修饰成分过多，过长，使得读者看不清楚这个句子在问什么。其实如果没有最后的那个prevalent theme的同位语a theme usually conveyed by more naturalistic modes of expression，本句会易懂得多。

意群训练：

In addition,  the style of  some Black novels,  like Jean Toomer's Cane,  verges on expressionism or surrealism； does this technique  provide a counterpoint  to the prevalent theme  that portrays  the fate against which  Black heroes are pitted,  a theme usually conveyed by  more naturalistic  modes of expression?

14. Black Fiction surveys a wide variety of novels，bringing to our attention in the　process some fascinating and little-known works like James Weldon　Johnson’s Autobiography of an Ex-　　Colored Man. （4）注意：bring A to B ——〉bring to B A
《黑人小说》考察了极为广泛的一系列小说，在此过程中让我们注意到了某些引人入胜但却鲜为人知的作品，如詹姆斯。韦尔登。约翰逊（James Weldon Johnson）的《一个曾经是有色人的自传》（Autobiography of an Ex-Colored Man）。

难句类型：倒装

解释：在以bringing开头的作状语的分词中出现了倒装，bring A to B被倒装为bring to B A,其倒装的原因仍是为了避免头重脚轻，正常的语序应该如下：bringing some fascinating and little-known works like James Weldon johnson's Autobiography of an Ex-Colored Man to our attention in the process.

意群训练：

Black Fiction surveys  a wide variety of novels， bringing to  our attention  in the　process  some fascinating  and little-known works  like James Weldon　Johnson's  Autobiography of an Ex-Colored Man.

15. Although these molecules allow radiation at visible wavelengths， where most of the energy of sunlight is concentrated，to pass through，they absorb some of the longer-wavelength，　　infrared emissions radiated from the Earth’s surface，radiation that would　otherwise be transmitted back into space. (4)
虽然这些分子允许可见波长（visible wavelength）的辐射——阳光的绝大部分能量就汇集于此——不受阻挡地穿透，但它们却会吸收某些较长波长（longer-wavelength），亦即从地球表面辐射出的红外发射（infrared emission），这种辐射若不是二氧化碳的缘故就会被重新输送回太空。

难句类型：复杂修饰、抽象词

解释：前面的分句中有一个不算很长的插入语，但是因为它插入的位置正好在固定搭配allow something to do somthing中间，将allow和to分得很远，所以读起来让人感觉很不舒服。

后面的分句中的最后一行radiation that would otherwise be transmitted back into space是其前面的infrared emissions的同位语。其中的otherwise是副词作状语，表示如果后面的分句所说的they absorb some of the longer-waverlength, infrared emissions不发生时的后果。

意群训练：

Although these molecules  allow radiation  at visible wavelengths，  where most of  the energy of sunlight  is concentrated， to pass through， they absorb  some of the longer-wavelength， infrared emissions radiated  from the Earth's surface， radiation that would　otherwise be  transmitted back  into space.

16. The role those anthropologists ascribe to evolution is not of dictating　the details of human behavior but one　of imposing constraints—ways of　feeling，thinking，and acting that　　"come naturally" in archetypal situations in any culture. （4）
这些人类学家所归诸于生物进化的作用，不是规定人类行为的种种细节，而是将各种限制强加于人类——即在任何文化的典型情景中都会“自然表露”的情感、思维、以及行动方式。

难句类型：复杂修饰、省略

解释：尽管我们很熟悉the role of something的这种表达，但本句中the role of被作者胜利很活。首先，在role后面有一个省略了引导词that的定语从句(因为role在从句中作ascribe的宾语)，这样就把role和系动词is隔得很远。其次，but前面的句子的主要结构The role is not of doing something其实是The role is not the role of doing something的省略形式，因为后面的the role与前面的完全重复，如果不把它省略掉，谁看到都要觉得啰嗦。因为同样的道理，but之后的one of imposing constraints实际上是is one role of imposing constraints的省略形式。

意群训练：

The role  those anthropologists  ascribe to evolution  is not of dictating　 the details of  human behavior  but one　of  imposing constraints— ways of　feeling， thinking，and acting  that　　"come naturally"  in archetypal situations  in any culture.  

17. Which of the following most probably provides an appropriate analogy from human morphology for the “details” versus “constraints” distinction made in the passage in relation to human behavior? （5）

以下哪一个选项最有可能为文章中所谈到的与人类行为有关的“人类行为细节”相对“人类所受限制”之间的差异，从人类形态的角度上提供了一个合适的类比？

难句类型：复杂修饰、抽象词

解释：本句子在所有GRE或GMAT阅读题的题干中是最难读懂的题干之一。本句不但结构复杂，而且用词抽象，使得读者如果想根据语义来搞清楚谁修饰谁，也变得极为困难。分析如下：本句的主干是Which of the following provides an analogy for the details versus constraints distinction?. Versus是一个介词，等于against，即体育比赛中的VS。其他的所有成分均是一些修饰成分。其中一个对答题最重要的限制条件是from human morphology，　说明这种类比的比较双方所比的必须是人类形态上的特征。

意群训练：

Which of the following  most probably  provides an appropriate analogy  from human morphology  for the "details"  versus "constraints"  distinction made in the passage  in relation to  human behavior?

18. A low number of algal cells in the presence of a high number of grazers suggested，but did not prove， that the grazers　had removed most of the algae. （3+）
在存在大量食草动物的同时却只有少量的水藻花粉囊，这暗示出——但没能证明——食草动物已吞噬了大部分水藻。

难句类型：插入语

解释：本句主语很长，而且谓语suggested与that引导的宾语从句间被插入语but did not prove隔开，造成阅读障碍。当suggest与but did not prove连在一起使用的时候，其意思不是建议，而是指一种基于主观臆测的推理，中文翻译成“暗示”。其英文释义为：to call to mind by though or association the explosion   suggested sabotage。GRE、GMAT及LSAT文章中，常用suggest，but do not prove来描述一种没有真凭实据、可能有问题的理论，然后在后面的叙述中把它否定掉。

意群训练：

A low number ofalgal cellsin the presence ofa high number of grazerssuggested，but did not prove，that the grazers　had removedmost of the algae.

19. Perhaps the fact many of these first studies considered only algae of a size that could be collected in a net (net phytoplankton), a practice that overlooked the smaller phytoplankton (nannoplankton) that we now know grazers are most likely to feed on , led to a de-emphasis of the role of grazers in subsequent research. （5）

可能这样一个事实，那就是很多这样的最初的研究只是考虑了那些能够用网捞起来的大小的水藻，这样一个忽视了更小的浮游生物（而这些浮游生物我们现在知道是捕食者主要的食物）的做法，导致了在接下来的研究中对于捕食者的作用的贬低。

难句类型：复杂修饰、插入语

解释：句子的结构繁杂。句子的主语令人吃惊地长，在最后一个逗号后的led以前，全是主语！其实句子的主干简单，就是the fact led to a de-emphasis of the role of grazers。但是本句的主语the fact后面的修饰成分长得吓人，先是个定语从句；定语从句中又套了一个定语从句。然后逗号后面的a practice引导的部分是前面的主语的同位语兼任插入语，practice后面的修饰它的一大堆东西又是定语从句套着定语从句。本句是典型的层层修饰结构。

意群训练：

Perhaps the fact thatmany ofthese first studiesconsidered only algaeof a sizethat could be collectedin a net(net phytoplankton), a pratice thatoverlooked the smallerthat we now knowgrazersare most likelyto feed on, led to a de-emphasisof the role of grazersin subsequent research.

20. Studies by Hargrave and Geen estimated natural community grazing rates by measuring feeding rates of　individual zooplankton species in the　laboratory and then computing community grazing rates for field conditions　using the known population density　of grazers. （5）
由哈格雷夫（Hargrave）和吉恩（Geen）所进行的研究，对自然条件下的群落捕食速率进行了估计，其手段是通过测量出实验室内单独的浮游动物种类的捕食速率，然后利用已知的食草动物种群密度，计算出实地状况下的群落捕食速率。

难句类型：复杂修饰

解释：本句对阅读者的阅读能力提出了更高的要求，不但要求读者读清楚句子的复杂的结构，而且对读者的词汇能力也提出了更高的要求。

By以前结构无需解释，by以后有两个作介词宾语短语的动名词结构，measuring和后面表示并列和顺接的and then之后的computing，说的是计算方法；前一个measuring说的是先算出实验室中浮游动物品种的单位捕食速率，后面的computing前其实省略了一个by，而且在这个动名词结构中还包括一个分词结构using the known population density of grazers，用已知的捕食者的种群密度计算出其野外的群体捕食速率。整个的by以后的计算过程简单了就是：实验室单位速率×野外密度＝野外群体速率

另外本句中的词汇也颇有迷惑性；虽然没有太难的单词，但是很多单词都是同义词和反义词，容易让人读混；（斜线分隔同义词，冒号分隔反义词）

estimate/measure/compute; feeding rates/grazing rates; zooplankton/grazers;  natureal/field; laboratory community; individuall

意群训练：

Studies by Hargrave and Geenestimated natural community graz-ing ratesby measuringfeeding rates of　individual zooplankton speciesin the　laboratoryand then computing community grazing ratesfor field conditions　using the knownpopulation density　of grazers.

21. In the periods　of peak zooplankton abundance，that is，in the late spring and in the summer，　　Haney recorded maximum daily community grazing rates，for nutrient-poor　lakes and bog lakes，respectively，of 6.6 percent and 114 percent of daily phytoplankton production. （3+）
在浮游动物数量激增的高峰期，亦即在春季后期以及夏季，哈尼记录了最大程度上的每日群落食草比率，对于营养物不充足的湖和沼泽湖而言，分别为每日浮游植物繁殖量的6.6%和114%.

难句类型：插入语

解释：句中有两组插入语，每组两个插入语，尤其是第二组，把rate of从中间劈开。不过因为句义尚好理解，所以本句只是有一点别扭，但不算太难。

意群训练：

In the periods　of　peak zooplankton abundance，that is，in the late spring and in the summer，Haney recordedmaximum daily community grazing rates，for nutrient-poor　lakesand bog lakes，respectively，of 6.6 percentand 114 percent ofdaily phytoplankton production.

22. The hydrologic cycle，a major topic in this science，is the complete cycle of phenomena through which water passes，beginning as atmospheric water vapor，passing into liquid and solid form as precipitation，thence along and into the ground surface，and finally again returning to the form of atmospheric water vapor by means of evaporation and transpiration. （4）
水文循环（hydrologic cycle），作为该学科中的一个主要课题，指的是水所经过的诸现象的整个循环过程，开始时是作为大气中的水蒸气，转而作为雨、雪、露、雹一类的降水量经过液体和固体形态，由此而沿着地层表面分布或进入地层表面，最终通过蒸发和散发作用再度回复到大气水蒸气的形态。

难句类型：复杂修饰、插入语、省略

水文循环（hydrologic cycle），作为该学科中的一个主要课题，指的是水所经过的诸现象的整个循环过程，开始时是作为大气中的水蒸气，转而作为雨、雪、露、雹一类的降水量经过液体和固体形态，由此而沿着地层表面分布或进入地层表面，最终通过蒸发和散发作用再度回复到大气水蒸气的形态。

解释：beginning开始的一系列分词都是修饰主语The hydrologic cycle的，分别是beginning/passing/passing/returning。值得注意的是，thence along and into the grund surfacee 是thence passing along and entering into the ground surfacee的省略形式，但是看上去意思却很清楚。类似这样的省略，是出题者合理地利用了省略来达到改编学术论文时压缩文章篇幅的目的。

意群训练：

The hydrologic cycle，a major topicin this science，is the complete cycle of phenomenathrough which water passes，beginning as atmospheric water vapor，passing into liquidand solid form asprecipitation，thence along and intothe ground surface，and finally again returning tothe form of atmosphericwater vaporby means ofevaporation and transpiration.

23. Only when a system possesses natural or artificial boundaries that associate the water within it the hydrologic cycle may the entire system properly be termed hydrogeologic.（4）

只有当一个系统拥有自然的或人工形成的边界来把边界中的水与水文循环联系起来的时候，才有可能把整个的系统恰当的成为与水文地质学有关。

难句类型：复杂修饰、倒装

解释：only放在句首时，主句的情态动词may倒装，这是我们高中就已经学过的东西。然而句首的only与倒装的may距离如此之远，这在以前却没有见过，所以读上去让人不习惯。另外一个难点在于，前面的由when所引导的时间状语从句中，宾语boundaries后面跟了一个定语从句，that associate the water within it with the hydrologic cycle,而且从句中的associate with又被water within it所分开，读者还要分神去考虑it所指的是什么，所以读到后面倒装的may的时候，难免不知所云。

意群训练：Only when a systempossesses naturalor artificial boundariesthat associate the waterwithin itwith the hydrologic cyclemay the entire system properlybe termed hydrogeologic.

24. The historian Frederick J. Turner wrote in the 1890’s that the agrarian discontent that had been developing　steadily in the United States since about 1870 had been precipitated by the　　closing of the internal frontier——that is，the depletion of available new land　needed for further expansion of the American farming system. （4）
史学家弗雷德里克.杰.特纳（Frederick J.Turner）于十九世纪九十年代著述道，美国约自18世纪70年代以来一直在持续不断发展的农民不满，由于国内边远地区（internal frontier）的封闭而更趋加剧——亦即是说，美国农业系统进一步扩展所必需的可资利用的新土地几近耗竭。

难句类型：复杂修饰

解释：典型的句子套句子。主句是F.J.T. wrote that，宾语从句中主干是the agrarian discontent had been precipitated by the closing of the internal frontier，在从句的主语the agrarian discontent后面又来了一个定语从句。

意群训练：

The historianFrederick J. Turnerwrote in the 1890’sthat the agrarian discontent thathad been developing　steadily inthe United States　since about 1870had been precipitated bythe　　closing of the internal frontier——that is，the depletion ofavailable new land　needed for further expansion of theAmerican farming system.

25. In the early 1950’s，historians who studied preindustrial Europe （which we may define here as Europe in the period from roughly 1300 to 1800） began， for the first time in large numbers，to　　investigate more of the preindustrial European population than the 2 or 3 percent who comprised the political　and social elite：the kings，generals，judges，nobles，bishops，and local　magnates who had hitherto usually filled history books. （4）
难句类型：复杂修饰、插入语

译文：二十世纪五十年代早期，研究前工业化时代欧洲（此处我们可将其界定为约自1300年至1800年这一时期的欧洲）的史学家，首次以众多的人数（杨鹏的书中：第一次以大量的数据），开始调查前工业化时代欧洲人口中的大多数，而非那些构成了政治与社会精英阶层的百分之二或三的人口，即国王、将军、法官、贵族、主教、以及地方上的达官显贵，而正是这部分人一直到那时为止普遍充斥于史学著作。

解释：句子中有两个插入语，一个是跟在preindustrial Europe之后的which we may define here as Europe in the period from roughly 1300 to 1800,这个插入语的直接作用是解释前面的preindustrial Europe的年代，而起到的客观作用则是把主句中的主语和谓语分割得很远；第二个插入语是在began，for the first time in large numbers, to investingate中间，把一个好好的began to斩为两段。

这句话另外一个难以理解的地方是more of the preindustrial European population than the 2 or 3 percent，表示的是在工业化以前的欧洲人口中超过了那2%到3%的人，亦即占97%到98%的人民群众。

意群训练：

In the early 1950’s，historians who studiedpreindustrial Europe （which we may definehere as Europein the period fromroughly 1300 to 1800） began，for the first timein large numbers，to　　investigatemore of the preindustrialEuropean populationthan the 2 or 3 percentwho comprised the political　and social elite：the kings，generals，judges，nobles，bishops，and local　magnateswho had hithertousually filled history books.

26. Historians such as Le Roy Ladurie　have used the documents to extract case　histories， which have illuminated the attitudes of different social groups （these attitudes include，but are not　　confined to，attitudes toward crime and　the law）and have revealed how the authorities administered justice. （3+

难句类型：复杂修饰、插入语

译文：象勒罗伊。拉迪里（Le Roy Ladurie）一类的史学家利用这些文献史料从中挖掘出某些个案史（case history）来，阐明了不同社会群体的态度（这些态度包括，但并非局限于，对犯罪和法律的态度），并揭示出当局是如何执行审判的。

解释：逗号以后的内容都是修饰逗号以前的case history的。在which引导的非限定性定语从句中有一个插入语(these attitudees includee, but are not confined to, attitudees toward crime and the law)，我们可以看到这个插入语中又套了一个插入语but not confined to。

意群训练：Historians such asLe Roy Ladurie　have usedthe documents toextract case　histories，which have illuminatedthe attitudes ofdifferent social groups（these attitudes include，but are not　　confined to，attitudes towardcrime and　the law）and have revealedhow the authoritiesadministered justice.

27. It can be inferred from the passage that a historian who wished to compare crime rates per thousand in a European city in one decade of the fifteenth century with crime rates in another decade of that century would probably be most aided by better information about which of the following? （5）

难句类型：复杂修饰

译文：从文章中可以推断出来，一个希望比较十五世纪以前一个十年的某个欧洲城市中的每千人的犯罪率与另外一个十年中的犯罪率的历史学家将会被以下那种信息的提高所最好的帮助？

解释：句首的it是形式主语，其具体内容是从that开始到句子结束的全部内容。That从句中，主语a historyian之后修饰它的超长的定语从句是这个句子难以读懂的原因。Compare crime rates with crime rates中间被修饰第一个crime rates的两个修饰成分perthousand in a European city in one decade of the fifteenth century分隔得很远。在with之后的第二个crime rates后面，省略了与前面重复的per thousand in a European city。

意群训练：

It can be inferredfrom the passage thata historianwho wished tocompare crime ratesper thousandin a European cityin one decade ofthe fifteenth centurywith crime ratesin another decadeof that centurywould probably bemost aided bybetter informationabout which of the following?

28. My point is that its central　consciousness—its profound understanding of class and gender　　as shaping influences on people’s lives—owes much to that earlier literary heritage，a heritage that，in general，has not been sufficiently valued by most contemporary literary critics. （4）

难句类型：复杂修饰、插入语

译文：我的论点是，其作品的中心意识——它将阶级和性别作为人们生活的决定性影响而作出的深邃理解——在很大程度上借鉴了那个早期的文学遗产，而这一遗产就总体而言还尚未获得大多数当代文学评论家的足够重视。

解释：宾语从句中的主语和谓语被长插入语分开，造成阅读障碍。插入语中有一个固定搭配understanding of A as B，是把A理解成B的意思。不过本句中as的宾语不容易理解：shaping influences on people’s lives可以理解成“形成了对人们生活的影响”也可以理解成“对人们生活的塑造性(决定性)影响”。当然后面的理解是正确的，然而在阅读现场想要在瞬间做出正确判断，还有赖于考生的阅读理解力和词汇功底的深浅。插入语后面还有一个固定搭配：A owes much to B，指前者有很多东西是来自于后者，得益于后者的。

意群训练：

My point is thatits central　consciousness—its profound understandingof class and gender　　as shaping influenceson people’s lives—owes much tothat earlier literary heritage，a heritage that，in general，has not beensufficiently valued bymost contemporary literary critics.

29. Even the requirement that biomaterials processed from these materials be nontoxic to host tissue can be met by techniques derived from studying the reactions of tissue cultures to biomaterials or from short-term implants.（5）

即使是这样的要求，即从这些材料中加工出来的生物材料应该对受移植者的组织无害，也能够通过从研究组织培养对生物材料的反应而来的，或从研究短期移植而来的技术来满足。

难句类型：复杂修饰、省略、专有名词、固定搭配

解释：主语the requirement后面带着一个长长的修饰主语的同位语；由于requirement的同位语中要求使用虚拟语气，所以其中的系动词成了原型(should be省略了should)。如此之长的修饰成分过后，谓语can be met与主语的关系已经很难理清了。从by开始的状语结构更为复杂；修饰techniques的后置的定语derived from studying the reactions of tissure cultures to biomaterials or derived from studying short-term implants实际上是由or所连接的两个固定搭配the reactions of tissure cultures to biomaterials；第二个derive from中还套了另外一个固定搭配the reactions of tissure cultures to biomaterials；第二个derive from则干脆把derive给省略了。此外，本句的专有名词奇多，这使得阅读的难度非常高。

意群训练：

Even the requirementthat biomaterialsprocessed fromthese materialsbe nontoxic tohost tissuecan be metby techniquesderived from studyingthe reactions oftissue culturesto biomaterials orfrom short-term implants.