要想清晰地把握学术性的托福阅读的文章结构框架，同学们首先应该具备分清句子与句子之间关系的能力。句间关系主要的常见类型:并列关系、转折关系或者是递进关系。每一种句间关系都会给文章的逻辑发展带来不一样的内容。

　　一.并列关系

　　并列关系的两句话主要意思方面有相通点，并且有时会有表示并列的关联词出现。例:

　　句子1：Most investigators concur that cer tain facial expressions suggest the same emotions in all people.

　　句子2：Moreover, people in diverse cultures recognize the emotions manifested by the facial expressions.

　　解释：句1调查者认同面部表情表明情感。句2人们识别表情表达出的情感。

　　并非所有并列关系的两个句子都有关联词出现，只要意思方面有联系逻辑符合即可。例：

　　句子1：Tunas, mackerels, and billfishes have made streamlining into an art form.

　　句子2：Their bodies are sleek and compact.

　　解析：句1流线成为艺术形式。句2身体光滑简洁。

　　意思方面不同，无关联词，仍为并列关系。因为句2的their代指句1的名词Tunas, mackerels, and billfishes。

　　常见表并列关系的关联词有：and, furthermore, in addition, additionally, similarly, likewise, as well as, besides, also, moreover, even等。

　　二.递进关系

　　递进关系又可以称为概述与详述关系。两句话意思方面相同，但前后两句是概述与详述的关系，或抽象与具体的关系。一般概述性或抽象内容涵盖内容广，但已引起歧义，可以让人们不禁问出how, what, why等问题。详述性或具体的句子相对于概述性或抽象句子具体且明确。例：

　　句子1Perhaps most important of all to these and other fast swimmers is their ability to sense and make use of swirls and eddies (circular currents) in the water.

　　句子2They can glide past eddies that would slow them down and then gain extra thrust by "pushing off" the eddies.

　　解析：句1与句2的意思方面均为swimmers运用swirls and eddies，但句1概述地描述为：sense and make use of, 句2出现具体动作描述glide past...and then gain extra thrust.

　　注意：考生应锻炼在阅读的同时就可以感受出句中概述性内容能力。以下形式常常可表示概述或抽象内容：

　　1.名词复数: causes, effects, adaptations, aspects, benefits等;

　　2.动词: benefit, develop, improve, evolve等动词;

　　3.形容词: important, innovative, great, intense, attractive, despondent等;

　　4.副词: successfully, hard, bravely, carefully等(往往与动词搭配)。

　　三.转折关系

　　转折关系的两句话总的来说一般用表示转折关系的关联词连接，意思方面来看有两种关系：意思的方面相同但意思相反、如例1，意思的方面不同，如例2。

　　例1:句子1It might be that a"stiff"lip suppresses emotional response -- as long as the lip is not quivering with fear ortension.

　　句子2But when the emotion that leads to stiffening the lip is more intense, and involves strong muscle tension, facial feedback may heighten emotional response.

　　解析：

　　句1a stiff lip suppresses emotional response

　　句2导致stiffening the lip的情感更加强烈时，facial feedback heighten emotional response。

　　例2:句子1The whale retained a tail and lacked a fluke, the major means of locomotion in modern cetaceans.

　　句子2The structure of the backbone shows, however, that Ambulocetus swam like modern whales by moving the rear portion of its body up and down, even though a fluke was missing.

　　解析：

　　句1鲸鱼保留尾巴，缺少现代鲸主要的推进工具：尾片。

　　句2背骨结构表明Ambulocetus与现代鲸游泳一样。

　　句1与句2意思方面不同，但用关联词however连接，仍未转折关系。