[求助]有人问过但没有回答的GWD-11-Q41

jinqijia

Q30: GWD-11-Q41:

Charcoal from a hearth site in Colorado, 2,000 miles south of Alaska, is known to be 11,200 years old.  Researchers reasoned that, since glaciers prevented human migration south from the Alaska-Siberia land bridge between 18,000 and 11,000 years ago, humans must have come to the Americas more than 18,000 years ago.

Which of the following pieces of new evidence would cast doubt on the conclusion drawn above?

A.    Using new radiocarbon dating techniques, it was determined that the charcoal from the Colorado site was at least 11,400 years old.

B.    Another campsite was found in New Mexico with remains dated at 16,000 years old.

C.    A computer simulation of glacial activity showed that it would already have been impossible for humans to travel south overland from Alaska 18,500 years ago.

D.    Using new radiocarbon dating techniques, it was proved that an ice-free corridor allowed passage south from the Alaska-Siberia land bridge at least 11,400 years ago.

E.     Studies of various other hunting-gathering populations showed convincingly that, once the glaciers allowed passage, humans could have migrated from Alaska to Colorado in about 20 years.

the answer is D。求大虾给解题思路。

CCAML

问哪个削弱

A.B 无关，C 加强， E无关。 D是与11400 年以前有一处无冰的通道可以通过。

jinqijia

谢谢楼上回答。如果D项中没有at least，我可以理解该项为正确答案。但是有at least 11,400 ago，11400<18000，怎么削弱啊？

jinqijia

up up

jinqijia

哪位NN帮帮忙？实在没想明白……等了一天还是没人理我……

妙妙cathy

D只是给出了一种情况包含于at least 11200 years ago，所以只要11400>11200就可以削弱了，

jinqijia

是我NC了。只要发现新证据表明在11200年前（即标准答案中的11400年前）有人类到达美洲的可能，原题可被削弱。谢谢！

TonyGe

结论：18000-11000 人不能过来，但是中间11400 people can passage,so undermine the conclusion.

cynthia1226

我还是不明白，at least 11400, 如果这条路的实际年龄是大于18000的，那还怎么削弱呢？

shalinzz

Charcoal from a hearth site in Colorado, 2,000 miles south of Alaska, is known to be 11,200 years old.  Researchers reasoned that, since glaciers prevented human migration south from the Alaska-Siberia land bridge between 18,000 and 11,000 years ago, humans must have come to the Americas more than 18,000 years ago.
Which of the following pieces of new evidence would cast doubt on the conclusion drawn above?
E1:C有11200年历史     E2:11000至18000年之间没有通道      C: c是18000年之前来的
A.    Using new radiocarbon dating techniques, it was determined that the charcoal from the Colorado site was at least 11,400 years old.  违反已知, 是11200,     中,不起作用
B.    Another campsite was found in New Mexico with remains dated at 16,000 years old. 中,不起作用
C.    A computer simulation of glacial activity showed that it would already have been impossible for humans to travel south overland from Alaska 18,500 years ago. 依然有可能是18000到18500之间到
D.    Using new radiocarbon dating techniques, it was proved that an ice-free corridor allowed passage south from the Alaska-Siberia land bridge at least 11,400 years ago. ---?11400年前有通道---?c可能在11400年到,削弱了原文
E.    Studies of various other hunting-gathering populations showed convincingly that, once the glaciers allowed passage, humans could have migrated from Alaska to Colorado in about 20 years. 中,无关