Argument Convincing Precise Slightly E Physicist Dreads Loses

意群训练： The physicist rightl y dreads precise argument , since an argumen t that is convincin g only if it is precis e loses all its forc e if the assumption s on which it is base d are slightly changed , whereas an argument that is convincin g though imprecis e may well be stabl e under small perturbation s of its underlying assumptions.

请思考：本句子中的主句加上从句加在一起一共有几个 ？

标志： 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)./

译文： 物理学家 正确地不敢做精确的论证 ，因为 一个（/只有当它是精确的时候/才令人信服的/论证 ，/（如果作为它的基础的）假设 发生了一点点变化 /就失去了 其全部说服力； 而 （一个尽管不很精确但是却令人信服的）论证 ，/（当作为它的基础的假设）稍有变动时，/仍有可能是稳定的 。

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 argument之后又跟了一个定语从句that is convincing though imprecise，修饰argument。whereas前面共有六个句子：由the physicist作主语的主句；由since的原因状语从句；修饰since从句中主语an argument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。

然而，在考试现场去数句子的数目，是只有呆子才会去干的事情。读者们惟一要干的事情，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。