TPO9托福阅读Passage1Colonizing the Americas via the Northwest Coast文本+题目原本+答案解析

Colonizing the Americas via the Northwest Coast

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. [■]

Support is growing for the alternative theory that people using watercraft, possibly skin boats, moved southward from Beringia along the Gulf of Alaska and then southward along the Northwest coast of North America possibly as early as 16,000 years ago. This route would have enabled humans to enter southern areas of the Americas prior to the melting of the continental glaciers. Until the early 1970s,most archaeologists did not consider the coast a possible migration route into the Americas because geologists originally believed that during the last Ice Age the entire Northwest Coast was covered by glacial ice. It had been assumed that the ice extended westward from the Alaskan/Canadian mountains to the very edge of the continental shelf, the flat, submerged part of the continent that extends into the ocean. This would have created a barrier of ice extending from the Alaska Peninsula, through the Gulf of Alaska and southward along the Northwest Coast of north America to what is today the state of Washington.

The most influential proponent of the coastal migration route has been Canadian archaeologist Knut Fladmark. He theorized that with the use of watercraft, people gradually colonized unglaciated refuges and areas along the continental shelf exposed by the lower sea level. Fladmark’s hypothesis received additional support from the fact that the greatest diversity in native American languages occurs along the west coast of the Americas, suggesting that this region has been settled the longest.

More recent geologic studies documented deglaciation and the existence of ice-free areas throughout major coastal areas of British Columbia, Canada, by 13,000 years ago. Research now indicates that sizable areas of southeastern Alaska along the inner continental shelf were not covered by ice toward the end of the last Ice Age. One study suggests that except for a 250-mile coastal area between southwestern British Columbia and Washington State, the Northwest Coast of North America was largely free of ice by approximately 16,000 years ago. Vast areas along the coast may have been deglaciated beginning around 16,000 years ago, possibly providing a coastal corridor for the movement of plants, animals, and humans sometime between 13,000 and 14,000 years ago.

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.

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.

TPO9托福阅读Passage1Colonizing the Americas via the Northwest Coast题目

Question 1 of 14： According to paragraph 1, the theory that people first migrated to the Americans by way of an ice-free corridor was seriously called into question by

A. paleoecologist Glen MacDonald's argument that the original migration occurred much later than had previously been believed

B. the demonstration that certain previously accepted radiocarbon dates were incorrect

C. evidence that the continental ice began its final retreat much later than had previously been believed

D. research showing that the ice-free corridor was not as long lasting as had been widely assumed

Question 2 of 14: The word “persuasively ” in the passage is closest in meaning to

A. aggressively

B. inflexibly

C. convincingly

D. carefully

Question 3 of 14: Paragraph 2 begins by presenting a theory and then goes on to

A. discuss why the theory was rapidly accepted but then rejected

B. present the evidence on which the theory was based

C. cite evidence that now shows that the theory is incorrect

D. explain why the theory was not initially considered plausible

Question 4 of 14: The phrase “prior to ” is closest in meaning to

A. before

B. immediately after

C. during

D. in spite of

Question 5 of 14: Paragraph 2 supports the idea that, before the 1970s, most archaeologists held which of the following views about the earliest people to reach the Americas?

A. They could not have sailed directly from Beringia to Alaska and then southward because, it was thought, glacial ice covered the entire coastal region.

B. They were not aware that the climate would continue to become milder.

C. They would have had no interest in migrating southward from Beringia until after the continental glaciers had begun to melt.

D. They lacked the navigational skills and appropriate boats needed long-distance trips.

Question 6 of 14：Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways to leave out essential information.

A. Because this region has been settled the longest, it also displays the greatest diversity in Native American languages.

B. Fladmark's hypothesis states that the west coast of the Americas has been settled longer than any other region.

C. The fact that the greatest diversity of Native American languages occurs along the west coast of the Americans lends strength to Fradmark's hypothesis.

D. According to Fladmark, Native American languages have survived the longest along the west coast of the Americas.

Question 7 of 14：The author's purpose in paragraph 4 is to

A. indicate that a number of recent geologic studies seem to provide support for the coastal hypothesis

B. indicate that coastal and inland migrations may have happened simultaneously

C. explain why humans may have reached America's northwest coast before animals and plants did

D. show that the coastal hypothesis may explain how people first reached Alaska but it cannot explain how people reached areas like modern British Columbia and Washington State

Question 8 of 14：The word “Vast ” in the passage is closest in meaning to

A. Frozen

B. Various

C. Isolated

D. Huge

Question 9 of 14：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

Question 10 of 14: The word “inhospitable ” in the passage is closest in meaning to

A. not familiar

B. not suitable

C. not dangerous

D. not reachable

Question 11 of 14：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

Question 12 of 14：The word “impetus ” in the passage is closest in meaning to

A. chance

B. protection

C. possibility

D. incentive

Question 13 of 14：Look at the four squares [■] that indicate where the following sentence could be added to the passage. Where could the sentence best fit?

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

Question 14 of 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.

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.

TPO9托福阅读Passage1Colonizing the Americas via the Northwest Coast解析

Question 1 of 14

正确答案：B

题目解析：B 以ice-free corridor做关键词定位至第二句和第四句，第二句只是单纯说这个理论是什么，问题问called into question遭到质疑为什么，所以答案应该在第四句。说这个理论crumble是因为GM先生发现radiocarbon dates是错的，所以答案B。

Question 2 of 14

正确答案：C

题目解析：A persuasively: 有说服力的，令人信服的。A是侵略地;B是不屈地;C是令人信服地;D是认真地。所以C的convincingly正确。

Question 3 of 14

正确答案：D

题目解析：D, 问题问先提出理论接着怎么了，所以看第二句。说这个路线能让人们在冰川融化之前进入美洲南部，所以这个是支持本段第一句内容的，而且后一句说直到70年代，人们才认同coast路线，也就是之前人们不认同这个理论，而后认为这个理论可能是对的。A和C都不对;原文没说前面的理论是基于这个事实的，B错，D正确。

Question 4 of 14

正确答案：A

题目解析：prior to: 在……之前。A是在…之前;B是紧接;C是在…期间;D是尽管。想到priority优先，所以A对。对应原文:This route would have enabled humans to enter southern areas of the Americas prior to the melting of the continental glaciers.前句说从白令海沿阿拉斯加湾向南，整个都在说走水路的事情，MS应该是冰化了之后，但原文特别强调进入美洲南部，也就是说人们通常是走冰川进入北部的，如果进入南部也是在冰川融化之后的话，就没有必要特别强调南部了。C在冰川融化期间没有信息;D尽管用的没必要。

Question 5 of 14

正确答案：A

题目解析：A 以1970s做关键词定位至第三句，70年代之前，人们都认为水路不可能，因为冰川覆盖了海面，所以A正确。B/C/D都没说。

Question 6 of 14

正确答案：C

题目解析：C 原句的结构是Fladmark的hypothesis得到了fact的支持。C说fact lend strength to他的hypothesis，所以正确。A的因果关系原文没有;原文说事实支持了hypothesis，B和D都说Fladmark说这个，偷换概念，都不对。

Question 7 of 14

正确答案：A

题目解析：A 问整段的目的，所以看第一句。研究表明那时候加拿大海岸没有冰，所以是支持由海路到达美洲的hypothesis，A或者D可能对，但D后半句的but在原文没说，所以A正确。不放心的话往后再看看，第二句又是一个research indicate blabla，所以A的a number of studies正确。

Question 8 of 14

正确答案：D

题目解析：vast: 巨大的。A是冻结的;B是各种各样的;C是孤立的，分离的;D是巨大的。所以D的huge正确。对应原文:Vast areas along the coast may have been deglaciated beginning around 16,000 years ago, possibly providing a coastal corridor for the movement of plants, animals, and humans sometime between 13,000 and 14,000 years ago. 原文说沿岸的怎么样的地区没有冰了，给人和动物提供了迁徙的通道，只有大片地方都没有冰，才能形成通道。既然没有冰，A的frozen一定错;B多样的错，因为原文没说很多地区;都形成通道了，C隔绝错。

Question 9 of 14

正确答案：C

题目解析：C以remains of large land animal做关键词定位至第一句，但这句明显只是问题的重复，所以往后看，下一句说inhospitable，再下一句说如果熊有吃的人也有，所以答案C正确。其他都没说。

Question 10 of 14

正确答案：B

题目解析：inhospitable: 不适于居住的，不好客的。A是不熟悉;B是不适合;C是不危险;D是不可获得。所以B不适合正确。对应原文:This is the time period in which most scientists formerly believed the area to be inhospitable for humans.下一句说如果熊有吃的人也有，就是人能活下来，inhospitable所在的这句因为有formerly believed就说明人们之前认为不能活下来，所以C不危险反了;A和D都没说。

Question 11 of 14

正确答案：B

题目解析：可以根据most recent geologic research定位到原文最后一句：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 between 13,000 and 14,000 years ago.这里说了在13,000和14,000年之间，B正确。这一段一共就三个地方提到了时间(第一句，最后两句)，快速扫过也可以迅速找到答案。

Question 12 of 14

正确答案：D

题目解析：impetus: 推动力，刺激。A是机会;B是保护;C是可能性;D是动机，刺激。所以D的incentive正确。对应原文: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. 原句说由于东西北三个方向都有障碍没法迁徙，所以人们往南飞行的什么更大。如果单纯带进去，A的chance和C的possibility都对，但这两个词的意思非常接近，所以都不对。protection完全不靠谱。

Question 13 of 14

正确答案：D

题目解析：D 四个过渡点，分别是moreover, other evidence, even if和exist。注意ice-free corridor由于反复出现，不能作为过渡点。通过moreover和other evidence排除A，因为first还没说不能说other;even if表让步，说明待插入句之前必须与待插入句意思上相反，只有D点前有不存在，与待插入句的exist相反，所以D对。C之后的he与前文过渡紧密;B的 but与之前过渡紧密。

Question 14 of 14

正确答案：BCE

题目解析：B.C. Eevidence选项是第一段的一个细节，不选。there is growing选项对应原文第二段第一句，正确。recent选项对应原文第四段最后一句，正确。research选项原文没说，不选。there is evidence选项对应原文第五段的后两句，正确。even though选项与第六段说的相反，北面已经住了很多人，不选。

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