og 39搜过了，没有问过

39.

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.

感觉这个题目没有看懂，或者是前因后果不太清楚，恳请指点

提干:人们最早在少于20000年前通过cross a land bridge到达北美的,但是最近又发现,在南美有32000年前的human shelters,所以,研究者就推测,人是先到达南美的,然后横渡太平洋到北美的.

问以下哪一项作为证据最反对推测

D是正确答案.

开始我考虑答案是D,然后想了想还是觉得是B.

D说南美人从32000年前到6000年前一直居住在哪儿没有动,但是没有一点意思否定推测出的那个人们活动的过程.而且有可能是在前5999年的时候,南美人横渡太平洋到北美的,因为提干说了"reached the Americas less than 20,000 years ago "5999小于20000

而B说北美人的住所比任何南美的都要早,这就完全说明了是先有北再有南,而不可能是先有南,再横渡太平洋到北的.

个人意见,如果欠妥,请各位NN指教!