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Most archaeologists have held that people first reached the Americas less than 20，000 years ago by crossing a land bridge into North America．But recent discoveries of human shelters in South America dating from 32，000 years ago have led researchers to speculate that people arrived in South America first，after voyaging across the Pacific，and then spread northward． Which of the following，if it were discovered，would be pertinent evidence against the speculation above? (A) A rock shelter near Pittsburgh , Pennsylvania , contains evidence of use by human beings 19 ,000 years ago． (B) Some North American sites of human habitation predate any sites found in South America． (C) The climate is warmer at the 32，000-year-old South American site than at the oldest known North American site． (D) The site in South America that was occupied 32，000 years ago was continuously occupied until 6，000 years ago． (E) The last Ice Age，between 11，500 and 20，000 years ago，considerably lowered worldwide sea levels． 答案是B。如果是一些人先到达SOUTH的地点A，然后其中有一部分人去了north，一部分人还留在south的地点A，当另一部分人到达north的地点B，留在south地点A的人又发现了south里的另一些地点C，那么B就在C之前，那么就不能反对结论了。我一开始是这样理解的，不知道问题出在哪里。
[此贴子已经被作者于2006-9-12 6:51:25编辑过] | 
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发表于 2006-9-12 03:02:00
