托福阅读常考话题及练习题推荐一：冰川（3）

► Paragraph 5：The coastal hypothesis has gained increasing support in recent years because the remains of large land animals, such as caribou and brown bears, have been found in southeastern Alaska dating between 10,000 and 12,500 years ago. This is the time period in which most scientists formerly believed the area to be inhospitable for humans. It has been suggested that if the environment were capable of supporting breeding populations of bears, there would have been enough food resources to support humans. Fladmark and other believe that the first human colonization of America occurred by boat along the Northwest Coast during the very late Ice Age, possibly as early as 14,000 years ago. The most recent geologic evidence indicates that it may have been possible for people to colonize ice-free regions along the continental shelf that were still exposed by the lower sea level between13,000 and 14,000 years ago.

9. According to paragraph 5, the discovery of the remains of large land animals supports the coastal hypothesis by providing evidence that

A. humans were changing their hunting techniques to adapt to coastal rather than inland environments

B. animals had migrated from the inland to the coasts, an indication that a midcontinental ice-free corridor was actually implausible

C. humans probably would have been able to find enough resources along the coastal corridor

D. the continental shelf was still exposed by lower sea levels during the period when the southward migration of people began

10. The word “inhospitable” in the passage is closest in meaning to

A. not familiar

B. not suitable

C. not dangerous

D. not reachable

11. According to paragraph 5, the most recent geologic research provides support for a first colonization of America dating as far back as

A. 16,000 years ago

B. 14,000 years ago

C. 12,500 years ago

D. 10,000 years ago

► Paragraph 6：The coastal hypothesis suggests an economy based on marine mammal hunting, saltwater fishing gathering, and the use of watercraft. Because of the barrier of ice to the east, the Pacific Ocean to the west, and populated areas to the north, there may have been a greater impetus for people to move in a southerly direction.

12. The word “impetus” in the passage is closest in meaning to

A. chance

B. protection

C. possibility

D. incentive

► Paragraph 1：It has long been accepted that the Americas were colonized by a migration of peoples from Asia, slowly traveling across a land bridge called Beringia (now the Bering Strait between northeastern Asia and Alaska) during the last Ice Age.  The first water craft theory about the migration was that around 11,000-12,000 years ago there was an ice-free corridor stretching from eastern Beringia to the areas of North America south of the great northern glaciers. It was the midcontinental corridor between two massive ice sheets-the Laurentide to the west-that enabled the southward migration.  But belief in this ice-free corridor began to crumble when paleoecologist Glen MacDonald demonstrated that some of the most important radiocarbon dates used to support the existence of an ice-free corridor were incorrect. He persuasively argued that such an ice-free corridor did not exist until much later, when the continental ice began its final retreat. 

13. Look at the four squares [ ] that indicate where the following sentence could be added to the passage.

Moreover, other evidence suggests that even if an ice-free corridor did exist, it would have lacked the resources needed for human colonization.

Where could the sentence best fit?

14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

Recent evidence favors a rival to the long-standing theory that the Americas were colonized 11,000-12,000 years ago by people migrating south from Beringia along a midcontinental ice-free corridor.

Answer Choices

A. Evidence that an ice-free corridor between two ice sheets developed when the continental ice first began to melt came primarily from radiocarbon dating.

B. There is growing support for the theory that migration took place much earlier, by sea, following a coastal route along Alaska and down the northwest coast.

C. Recent geologic evidence indicates that contrary to what had been believed, substantial areas along the coast were free of ice as early as 16,000 years ago.

D. Research now indicates that the parts of the inner continental shelf that remained covered with ice were colonized by a variety of early human groups well adapted to living in extremely cold environments.

E. There is evidence suggesting that areas along the coast may have contained enough food resources between 13,000 and 14,000 years ago to have made human colonization possible.

F. Even though the northern part of the continent allowed for a more varied economy, several early human groups quickly moved south.

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