Native Americans probably arrived from Asia in successive waves over several millennia, cr
ossing a plain hundreds miles wide that now lies inundated by 160 feet of water released by melting glaciers. For several periods of time, the first beginning around 60,000 B.C. and the last ending around 7.000 B. C. , this land bridge was open. The first people traveled in the dusty trails of the animals they hunted. They brought with them not only their families, weapons, and tools but also a broad metaphysical understanding, sprung from dreams and visions and articulated in myth and song, which complemented their scientific and historical knowledge of the lives of animals and of people. All this they shaped in a variety of languages, bringing into being oral literatures of power and beauty.
Contemporary readers, forgetting the origins of western epic, lyric, and dramatic forms, are easily disposed to think of "literature" only as something written. But on reflection it becomes clear that the more critically useful as well as the more frequently employed sense of the term concerns the artfulness of the verbal creation, not its mode of presentation. Ultimately, literature is aesthetically valued, regardless of language, culture, or mode of presentation, because some significant verbal achievement results from the struggle in words between tradition and talent. Verbal art has the ability to shape out a compelling inner vision in some skillfully crafted public verbal form.
Of course, the differences between the written and oral modes of expression are not without consequences for an understanding of Native American literature. The essential difference is that a speech event is an evolving communication, an "emergent form", the shape, functions, and aesthetic values of which become more clearly realized over the course of the performance. In performing verbal art, the performer assumes responsibility for the manner as well as the content of the performance, while the audience assumes the responsibility for evaluating the performer's competence in both areas, It is this intense mutual engagement that elicits the display of skill and shapes the emerging performance. Where written literature provides us with a tradition of texts, oral literature offers a tradition of performances.
According to the Passage, why did the first people who came to North America leave their homeland？
A．They were hoping to find a better climate.
B．They were seeking freedom.
C．They were following instructions given in a dream.
D．They were looking for food.
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