18. 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 correctedequation is itself only an imperfect approximation to an infinite set ofquantum 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.
19. The physicist rightly dreads precise argument，since an argument that isconvincing only if it is precise loses all its force if the assumptions onwhich 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.
20. 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.◎
21. As my own studies have advanced，I have been increasingly impressed with the functionalsimilarities 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.
22. 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 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.
23. 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?
24. 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?
25. Black Fiction surveys a wide variety of novels，bringing to our attention in theprocess some fascinating and little-known works like James WeldonJohnson’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 theprocess some fascinating and little-known works like James WeldonJohnson''s Autobiography of an Ex-Colored Man.
