1、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.

　　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.

　　2、 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.

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