很多托福阅读段落属于总-分结构，即段落开始为段落主题句，其他部分为支撑细节，具体论证方式有举例、对比比较、定义、分类、提供数据支持、类比、过程描述等，此时的段落目的对应段落开始的主题句。例如：

　　例一(总-分结构)

　　Paragraph 7: About 90 percent of modern humans are right-handed: we are the only mammal with a preferential use of one hand. The part of the brain responsible for fine control and movement is located in the left cerebral hemisphere, and the findings above suggest that the human brain was already asymmetrical in its structure and function not long after 2 million years ago. Among Neanderthalers of 70,000–35,000 years ago, Marcellin Boule noted that the La Chapelle-aux-Saints individual had a left hemisphere slightly bigger than the right, and the same was found for brains of specimens from Neanderthal, Gibraltar, and La Quina.

　　What is the author's primary purpose in paragraph 7?

　　(A) To illustrate the importance of studying the brain

　　(B) To demonstrate that human beings are the only mammal to desire fine control of movement

　　(C) To contrast the functions of the two hemispheres of the brain

　　(D) To demonstrate that right-hand preference has existed for a long time

　　根据一般段落的总-分结构，可以判断首句为主题句，所以第四个选项为正确答案。文中主要描述大脑左半球的功能，未与大脑右半球的功能进行比较，所以第三个选项为干扰选项。

　　例二(总-分结构)

　　Paragraph 6: Moreover, getting petroleum out of the ground and from under the sea and to the consumer can create environmental problems anywhere along the line. Pipelines carrying oil can be broken by faults or landslides, causing serious oil spills. Spillage from huge oil-carrying cargo ships, called tankers, involved in collisions or accidental groundings (such as the one off Alaska in 1989) can create oil slicks at sea. Offshore platforms may also lose oil, creating oil slicks that drift ashore and foul the beaches, harming the environment. Sometimes, the ground at an oil field may subside as oil is removed. The Wilmington field near Long Beach, California, has subsided nine meters in 50 years; protective barriers have had to be built to prevent seawater from flooding the area. Finally, the refining and burning of petroleum and its products can cause air pollution. Advancing technology and strict laws, however, are helping control some of these adverse environmental

　　In paragraph 6, the author’s primary purpose is to

　　(A)provide examples of how oil exploration can endanger the environment

　　(B)describe accidents that have occurred when oil activities were in progress

　　(C)give an analysis of the effects of oil spills on the environment

　　(D)explain how technology and legislation help reduce oil spills

　　根据段落的总-分结构(段落首句中的复数名词problems说明本段落的结构是总-分结构——首句总论，其他句子分述几个problems)，可以确定首句为段落主题句，即本段的写作目的，第一个选项符合此意，为正确答案。第二个选项只是论证本身的内容，不是段落首句所说的写作目的。第三个选项与第四个选项都只是段落论述中的细节。

　　例三(特殊结构)

　　Paragraph 5: In addition to exploring the possible antecedents of theater, scholars have also theorized about the motives that led people to develop theater. Why did theater develop, and why was it valued after it ceased to fulfill the function of ritual? Most answers fall back on the theories about the human mind and basic human needs. One, set forth by Aristotle in the fourth century B.C., sees humans as naturally imitative—as taking pleasure in imitating persons, things, and actions and in seeing such imitations. Another, advanced in the twentieth century, suggests that humans have a gift for fantasy, through which they seek to reshape reality into more satisfying forms than those encountered in daily life. Thus, fantasy or fiction (of which drama is one form) permits people to objectify their anxieties and fears, confront them, and fulfill their hopes in fiction if not fact. The theater, then, is one tool whereby people define and understand their world or escape from unpleasant realities.

　　Which of the following best describes the organization of paragraph 5?

　　(A)The author presents two theories for a historical phenomenon.

　　(B)The author argues against theories expressed earlier in the passage.

　　(C)The author argues for replacing older theories with a new one.

　　(D)The author points out problems with two popular theories.

　　本段首句中的motives说明作者想探讨戏剧起源的动机，但是作者未直接说明这些动机，而是以一个问句将戏剧起源这一现象戏剧化。接着给出了两个答案，等于给一个现象提供了两个解释。第一个选项符合此意，为正确答案。

　　其实只要掌握托福阅读文章的几种段落组织方式，每种文章结构的主旨词，在托福阅读练习中，保持对主旨词的敏感性，熟练之后就能快速把握托福阅读段落的主旨了，托福阅读成绩也就自然提升了。