接下来本文就以Official Guide 当中的一篇文章及附带的6个问题为例，简要作一个分析，旨在让学生清楚地了解科学推理题目的基本解题思路。

　　Passage IV

　　Three studies were conducted to examine the relation shop between ants and acacia trees they inhabit.

　　解题的第一步首先是审题。第一步就是要读最前边的一段论述性文字，在这一步骤中，重点关注这篇文章的主体，也就是主要研究对象，这里当然也就是ants and acacia trees they inhabit。以下每个实验研究的介绍处理方法一样，扫读，重点关注其分别的次级研究对象就足够了。强调一点，次级研究对象一定是紧密围绕着主要研究对象的。以上就是我们对审题的要求。

　　Study 1

　　Table 1 shows the results of a comparison between a species of acacia tree that is inhabited by ants (ant trees) and a species that is not inhabited by ants (non-ant trees).

　　Table 1

　　Ant trees Non-ant trees

　　Leaves bitter-tasting chemicals absent

　　protein-bodies present bitter-tasting chemicals present

　　protein-bodies absent

　　Thorns specialized hollow thorns on stems no specialized thorns

　　Ants specific ant species living in thorns no ants living on trees

　　Exrafloral nectaries present absent

　　Trunk surrounded by bare ground surrounded by many other plants

　　﹡Nectar-producing (sugar-producing) structures located outside the flowers

　　Study 2

　　Table 2 shows the results of a comparison between acacia ant and a closely related ant species that does not inhabit acacia trees.

　　Table 2

　　Acacia ants Non-acacia ants

　　Aggressiveness very aggressive very aggressive

　　Active periods active day and night active during daylight only

　　Diet protein-bodies

　　nectar do not eat living plants

　　Nest site only in the thorns of ant trees in the ground

　　Study 3

　　Acacia trees were divided into three groups. Acacia ants were removed from the trees in group A, but were left on the trees in Group B. Group C consisted of a species of non-ant acacia tree. All the trees were initially healthy and of similar size, the number of trees still alive in each group 300 days after the start of the study is shown in Table 3

　　Table 3

　　Group A Group B Group C

　　Day alive dead alive dead alive dead

　　1

　　300 38

　　10 0

　　28 39

　　28 0

　　11 40

　　30 0

　　10

　　Trees in Group A were killed by plant-eating insects and large mammals that ate the leaves on lower branches. There was no evidence that trees in Groups B and C were killed by grazing animals.

　　18. How is the designs of study 1 different from the design of study 2?

　　F. In study 1, acacia ants were removed from acacia trees, but not in Study 2.

　　G. in study 1, plant characteristics were examined, while in Study 2, ant characteristics were examined.

　　H. In study 1, acacia ants were examined, while in Study 2, non-acacia ants were examined.

　　J. In study 2, ant characteristics were examined, while in Study 2, plant characteristics were examined.

　　第一道题目往往比较简单。这里我们看到题目问的是Study1和2比较起来有什么不同?如果Study1和2的介绍和表格的内容来看，不同点有很多，那到底题目要求的不同点应该是那个呢?当然，问到实验设计的不同，一定是问的实验的目的和方法不同，这里也就是问其研究对象的不同，其他的差异，诸如实验结果，实验数据的差异不是题目的要求。那么这里，很明显答案是(G.)

　　19. On the basis of the experimental results, one can generalize that which of the following characteristics protects non-ant acacias from being eaten by insects or grazing animals?

　　A. Bitter-tasting chemicals

　　B. Protein bodies

　　C. Extrafloral nectaries

　　D. Specialized hollow thorns