模式二：
第一部分：开头提出一个概念、一个中心思想或者一种现象；
第二部分：围绕着这个概念、中心思想或者现象，从各个方面进行分析和解释说明，这种文章比较容易定位其主旨；
第三部分：对文章进行总结，并再一次对该概念、中心思想进行阐述，或对相关现象进行说明。
例文：2000年Passage 5
If ambition is to be well regarded, the rewards of ambition health, distinction, control over one's destiny must be deemed worthy of the sacrifices made on ambition's behalf. If the tradition of ambition is to have vitality, it must be widely shared; and it especially must be highly regarded by people who are themselves admired, the educated not least among them. In an odd way, However, it is the educated who have claimed to have give up on have give up on ambition as an ideal. What is odd is that they have perhaps most benefited from ambition-if not always their own the that of their parents and grandparents. There is heavy note of hypocrisy in this, a case of closing the barn door after the horses have escaped with the educated themselves riding on them.
Certainly people do not seem less interested in success and its signs now than formerly. Summer homes, European travel, BMWs. The locations, place names and name brands may change, but such items do not seem less in demand today than a decade or two years ago. What has happened is that people cannot confess fully to their dreams, as easily and openly as once they could, lest they be thought pushing, acquisitive and vulgar. Instead, we are treated to fine hypocritical spectacles, which now more than ever seem in ample supply: the critic of American materialism with a Southampton summer home; the publisher of radical books who takes his meals in three-star restaurants; the journalist advocating participatory democracy in all phases of life, whose own children are enrolled in private schools. For such people and many more perhaps not so exceptional, the proper formulation is, Succeed at all costs but avoid appearing ambitious.
The attacks on ambition are many and come from various angles; its public defenders are few and unimpressive, where they are not extremely unattractive. As a result, the support for ambition as a healthy impulse, a quality to be admired and fixed in the mind of the young, is probably lower than it has ever been in the United States. This does not mean that ambition is at an end, that people no longer feel its stirrings and promptings, but only that, no longer openly honored, it is less openly underground, or made sly. Such, then, is the way things stand: on the left angry critics, on the right stupid supporters, and in the middle, as usual, the majority of earnest people trying to get on in life.
这篇文章主要围绕着地质活动的热点（hot pot）理论这个概念进行讨论。
