Theories on early human migration to the Americas

文章大意

讲座探讨人类从亚洲迁徙到美洲的时间、方式和原因。提到白令陆桥理论，即约7.5万至1.4万年前通过干草原陆桥从西伯利亚到阿拉斯加，并南下。但阿拉斯加证据仅1.3万年，而智利蒙特维德遗址生物遗存超1.4万年，引发对传统理论的质疑。

题目与答案

1. Humans migrated from Northern Asia to Alaska via a land bridge.

   The area consists of a dry grassland plain up to 2000km.

   The winter is cold and long with strong winds but tree from 31_____ .

   答案：ice

   原文定位：They think this environment would have been similar to present-day tundra, with long, cool winters and perpetual winds, but crucially, no ice

   同义替换：「winter is cold and long」↔「long, cool winters」

2. The earliest group of humans followed 32_____ to Alaska.

   答案：animals

   原文定位：The theory is that these first humans were hunting animals, which they followed into what is now Alaska

   同义替换：「earliest group of humans」↔「first humans」

3. Anthropologists found similar shaped 33_____ in people in Northern Alaska and in North America.

   答案：teeth

   原文定位：For example, anthropologists have found a high incidence of similarly shaped teeth in people in Northern Asia and in North America

4. The land is covered with glaciers,which makes it difficult to find 34_____.

   答案：resources

   原文定位：because much of the land would have still been covered in glaciers, and it would have been very hard to find resources

   同义替换：「makes it difficult to」↔「very hard to」

5. The other evidence was in the form of 35_____ for hunting.

   答案：weapons

   原文定位：This was in the form of weapons used for hunting

6. Some scientists believe first settlers moved from North to South.

   But no 36_____ have been found to support the theory.

   答案：boats

   原文定位：Although no boats have been discovered yet to support this theory

   同义替换：「But」↔「Although」，「found」↔「discovered」

7. Scientists found a variety of 37_____ in the sea,such as seaweed.

   答案：plants

   原文定位：Scientists were surprised to discover nine species of marine plants, including seaweed

   同义替换：「a variety of」↔「nine species of」，「in the sea」↔「marine」

8. However, some archaeologists did not believe that first humans arrived via Alaska.

   They thought the 38_____ was too bad for humans to survive in.

   答案：climate

   原文定位：They say that at this time, the climate in Alaska would have been too inhospitable for humans to survive in

   同义替换：「bad」↔「inhospitable」

9. They doubt the 39_____ skills of the early people for such a long voyage.

   答案：navigational

   原文定位：Many scientists doubt that people at this time had the navigational expertise for such a long voyage

   同义替换：「skills」↔「expertise」

10. People believe the theory due to there is a strong 40_____ in the Pacific Ocean.

    答案：current

    原文定位：People who support this theory believe that crossing the Pacific would have been possible because of a powerful current in the Pacific Ocean

    同义替换：「believe」↔「support」，「due to there is a strong」↔「because of a powerful」