Aristotle believed that man could arrive at an understanding of reality by reasoning from self-evident principle.

　　Aristotle's natural science dominated the Western thought for two thousand years.

　　Self-evident principle is that everything in the universe has its proper place, hence one can deduce that objects fall to the ground because that’s where it belongs.

　　【翻译】举个例子吧，亚里士多德，他的自然科学理论统治了整个西方思想长达两千年之久。他认为，人们可以通过一些显而易见的法则推断来达到对现实的理解。这种不证自明的法则就是，任何事件在宇宙中总有其合适的位置。因而人们可以推断出，物体掉到地上是因为物体本身就属于大地的。

　　Both you and she know that / if you are not sure what you want, you are not likely to find it.(1988年真题)

　　【分析】that if 属于常考结构，对于这种结构的理解关键在于学会对that if 结构进行断句。在理解的时候，that if 之间语义应稍作停顿，把if与后面引导的状语从句语义连贯起来。

　　【翻译】你和她都知道，如果你不能确定你所想要的东西，那么你就没有可能找到它。

　　The mineral elements from the soil / that are usable by the plant / must be dissolved in the soil solution / before they can be taken into the root. (1991年真题)

　　【分析】句子主干为：The mineral elements must be dissolved in the soil solution before they can be taken into the root.定语从句“that are usable by the plan”是修饰“The mineral elements”；“from the soil”是介词短语作状语。该句可理解为以下简单句的句意组合：

　　The mineral elements from the soil must be dissolved in the soil solution before they can be taken into the root.

　　The mineral elements are usable by the plan.

　　【翻译】土地里被植物所用到的矿物质元素只有在土地里先期溶解，才能被植物的根吸收。

　　C.R.Darnes has suggested that / it is as proper to term the plant a water structure / as to call a house composed mainly of brick / a brick building. (1991年真题)

　　【分析】这里是由as...as...(像……¬一样，正如……¬一样)连接两个并列成分构成的长句。该句的主干为：C.R.Darnes has suggested that / it is as proper to term the plant a water structure / as to call a house a brick building.“composed mainly of brick”是分词作状语修饰“a house”。这里把“砖与房子的关系比做水与植物的关系说明水对于植物的重要性”。

　　【翻译】C.R.Darnes认为，正如把一栋主要由砖建造的建筑称为砖瓦建筑一样，我们可以把植物看作一种水体结构。

　　To be promoted or to fall behind / is not a matter of salary but /even more a matter of self-respect. This constant need to prove / that one is as good as or better than one's fellow-competitor / creates constant anxiety and stress, the very causes of unhappiness and illness. (1993年真题)

　　【分析】第一句主要是not...but...(不是……¬而是……¬）的理解。第二句主干：This constant need to prove creates constant anxiety and stress.句子主干中“This constant need to prove”是不定式短语作主语。 “that one is as good as or better than one's fellow-competitor”是对This constant need to prove的同步说明。“the very causes of unhappiness and illness”是对“constant anxiety and stress”的同步说明。