Informative的文章目的在于inform the reader，文章不会支持关于一个问题的任何一方，尽管他们可能会在文章中讲其他人的观点;Argumentative的文章会讲解作者自己的观点，而且作者会用其他的信息来支持这个观点。文章的主要目的是用特定的证据以及逻辑框架来支持自己的论断。 2.2如何寻找说明文大意 (Big picture) 为了寻找文章的Big picture, 这里强烈建议读者在阅读篇章的过程中mark重要的内容。对于不同类型的文章我们mark的内容当然也是不同的。 Narrative的文章：作者的Emotion(或Emotion发展变化的过程) Informative—summary：具体的事物 Informative—analysis: the author’s analysis, tone, opinion Argumentative—Argue for: Main Point, Conclusion/Concession Argumentative—Argue Against: others’ opinion, the author’s opinion Paired Passages—Common, Main Point or Emotion of each passage Informative(说明文)的篇章来源包括人文学，社会科学以及自然科学。现在我们来看Informative类的文章如何mark,寻找big picture的例子。
例一： In many respects living Native Americans remain as mysterious, exotic, and unfathomable to their contemporaries at the end of the twentieth century as they were to the Pilgrim settlers over three hundred fifty years ago. Native rights, motives, customs, languages, and aspirations are misunderstood by Euro-Americans out of a culpable ignorance that is both self-serving and self-righteous. Part of the problem may well stem from the long-standing tendency of European or Euro-American thinkers to regard Native Americans as fundamentally and profoundly different, motivated more often by mysticism than by ambition, charged more by unfathomable visions than by intelligence or introspection. This idea is certainly not new. Rousseau’s* “noble savages” wandered, pure of heart, through a pristine world. Since native people were simply assumed to be incomprehensible, they were seldom comprehended. Their societies were simply beheld, often through cloudy glasses, and rarely probed by the tools of logic and deductive analysis automatically reserved for cultures prejudged to be “civilized.” And on those occasions when Europeans did attempt to formulate an encompassing theory, it was not, ordinarily, on a human-being-to-human-being basis, but rather through an ancestor-descendant model. Native Americans, though obviously contemporary with their observers, were somehow regarded as ancient, examples of what Stone Age Europeans must have been like. It’s a great story, an international crowd pleaser, but there is a difficulty: Native Americans were, and are, Homo sapiens sapiens. Though often equipped with a shovel-shaped incisor tooth, eyes with epicanthic folds, or an extra molar cusp, Native American people have had to cope, for the last forty thousand years or so, just like everyone else. Their cultures have had to make internal sense, their medicines have had to work consistently and practically, their philosophical explanations have had to be reasonably satisfying and dependable, or else the ancestors of those now called Native Americans would truly have vanished long ago. The reluctance in accepting this obvious fact comes from the Eurocentric conviction that the West holds a monopoly on science, logic, and clear thinking. To admit that other, culturally divergent viewpoints are equally plausible is to cast doubt on the monolithic center of Judeo-Christian belief: that there is but one of everything—God, right way, truth—and Europeans alone knew what that was. If Native American cultures were acknowledged as viable, then European societies were something less than an exclusive club. It is little wonder, therefore, that Native Americans were perceived not so much as they were but as they had to be, from a European viewpoint. They dealt in magic, not method. They were stuck in their past, not guided by its precedents. Such expedient misconception argues strongly for the development and dissemination of a more accurate, more objective historical account of native peoples—a goal easier stated than accomplished. Native American societies were nonliterate before and during much of the early period of their contact with Europe, making the task of piecing together a history particularly demanding. The familiar and reassuring kinds of written documentation found in European societies of equivalent chronological periods do not exist, and the forms of tribal record preservation available—oral history, tales, mnemonic devices, and religious rituals— strike university-trained academics as inexact, unreliable, and suspect. Western historians, culture-bound by their own approach to knowledge, are apt to declaim that next to nothing, save the evidence of archaeology, can be known of early Native American life. To them, an absolute void is more acceptable and rigorous than an educated guess. However, it is naïve to assume that any culture’s history is perceived without subjective prejudice. Every modern observer, whether he or she was schooled in the traditions of the South Pacific or Zaire, of Hanover, New Hampshire, or Vienna, Austria, was exposed at an early age to one or another form of folklore about Native Americans. For some, the very impressions about Native American tribes that initially attracted them to the field of American history are aspects most firmly rooted in popular myth and stereotype. Serious scholarship about Native American culture and history is unique in that it requires an initial, abrupt, and wrenching demythologizing. Most students do not start from point zero, but from minus zero, and in the process are often required to abandon cherished childhood fantasies of superheroes or larger-than-life villains. 读者可以自行用3分钟的时间来寻找一下这篇文章的Big picture。 这是一篇偏Informative—Analysis的一篇文章。 Problemà Causeà Deep Analysis of CauseàSolution 这是一篇典型的“问题分析+问题解决”类型的文章 Problem: (Paragraph 1) remain as mysterious, exotic, and unfathomable to their contemporaries Cause: (Paragraph 1) Part of the problem may well stem from Deep Analysis: (Paragraph 2—5) Paragraph 3: through an ancestor-descendant model Paragraph 4: Eurocentric conviction Paragraph 5: misconception of European Historians Solution: demythologizing 例二： Aviation belonged to the new century in part because the engineering that went into flying machines was utterly different from that of the Industrial Revolution. Nineteenth-century engineering revolved around the steam engine. It was about weight and brute power—beautifully machined heavy steel, burnished bronze, polished copper pipes, ornamental cast iron—everything built, with no expense spared, to withstand great pressures and last any number of lifetimes. Airplane construction was the opposite of all that; it was about lightness. The Wright brothers, who created one of the first airplanes, started out making bicycles, which were all the rage at the turn of the century. They knew about thin-wall steel tubes, wire-spoked wheels, chain droves, and whatever else it took to construct efficient machines that weighed as little as possible. In effect, they were practical engineers at the cheap end of the market, but they happened to be fascinated by flight. Says one writer, “Wilbur [Wright] spent his time studying the flight of vultures, eagles, ospreys, and hawks, trying to discover the secret of their ability to maneuver with their wings in unstable air. To those who later asked him how he learned to fly, he loved to reply through his scarcely opened lips: ‘Like a bird.’” This is the point at which engineering intersects with the imagination, with humanity’s ancient dream of freeing itself from gravity. Until the first fliers got to work, the body was earthbound, but it enclosed a soul that flew—in meditation, in poetry, and, as the seventeenth-century English poet Andrew Marvell showed, sometimes spectacularly in both: Casting the body’s vest aside My soul into the boughs does glide: There, like a Bird, it sits and sings, Then whets and combs its silver wings, And, till prepared for longer flight, Waves in its plumes the various light. At the beginning of this century, the new light engineering that allowed people to fly seemed to the uninitiated a kind of poetry. In 1913, a writer in the Atlantic Monthly claimed that “machinery is our new art form” and praised “the engineers whose poetry is too deep to look poetic” and whose gifts “have swung their souls free … like gods.” One of Wright’s most eloquent admirers called him a poet and compared him to one of “those monks of Asia Minor who live perched on the tops of inaccessible mountain peaks. The soul of Wilbur Wright is just as high and faraway” Wright was, in fact, “deeply middle-class and unheroic,” writes one biographer, but those obsessed with the glamour of flight pretended not to notice. 以上黑体加粗的地方是这篇文章所出现的事物: aviation, airplane, Wright brothers, poetry, new light engineering, a writer……，所有这些事物都表明这篇文章是一个Informative—summary. 基本上文章的BP很简单，包括：为什么Wright Brothers发现飞机、飞机的发现对人们想象力的影响、人们对Wright Brothers的过于神化。
