Question

     The mystery of why humans are the only animals to have chins (下巴) may have been solved by scientists who suggest that it is connected to the invention of cooking.

    A paper from the University of Florida tries to explain exactly why humans 一 unlike all other primates (灵长目动物) 一have chins.

     A team led by Dr James Pampush collected information from more than 100 kinds of primate and compared it with historical information. Computer modelling found how the chin developed.

    Random genetic change(随机的基因变化)was ruled out because the chin developed 77 times faster than the average genetic change. And the study finds no evidence that it -served a useful purpose. The research,published in the Journal of Human Evolution,suggests the chin is a by-product of another event. In this case,the event could well be the invention of cooking.

     “The chin began to appear as a result of major changes six million years earlier. The arrival of cooking and softer food meant humans no longer needed big teeth and powerful jaws .and over the next two million years to 200,000 years both got smaller and the chin was bora ,” said Dr Pampush. “My guess is that it most likely happened around two million years ago when there was a jump in brain size. The changes which finally lead to the chin are directly related to cooking,and indirectly related to larger brains and bodies."

     Dr Pampush's new theory goes against previous suggestions that the chin was an example of sexual selection,with attractive chins marking out men who are likely to make good mates(配偶) . The fact that both men and women have chins means the theory is unlikely.

     Another theory put forward in the past said that the chin was a way to balance out the stress of chewing,but Dr Pampush also threw doubt on that idea.

1. The reason why we have chins .

   A. is connected to humans’ action of chewing

   B. has something to do with cooking

   C. is random genetic change

   D. is related to eating time

2. How did the researchers get their result?

   A. By carrying out experiments. .

   B. By studying scientific theories.

   C. By examining the human brain.

   D. By comparing recorded information.

3. Before developing chins,humans .

   A. had bigger teeth

   B. cooked softer food

   C. had smaller jaws

   D. had larger bodies

4. According to Dr Pampush,the chin most

probably appeared around .

   A. 6 million years ago

   B. 4  million years ago

   C. 2  million years ago

   D. 0.2 million years ago

5. What does the underlined part “the theory” refer to?

   A. Men are likely to have more attractive chins.

   B. The chin helps humans attract a mate.

   C. Both men and women have chins.

   D. Dr Pampush's theory.

Answer 1

1. B. 细节理解题。根据第一段中的it is connected to the invention of cooking 可知，人类有下巴与烹饪的发明有关。

2. D. 写作手法题。根据第三段中的A team led by Dr James Pampush collected information from more than 100 kinds of primate and compared it  with historical information 可知，研究 人员是通过数据比较得出的结果

100 kinds of pnmate and compared it with historical information 可知，研究 人员是通过数据比较得出的结果。

3. A.推理判断题。根据倒数第三段中 的 The arrival of cooking and softer food meant humans no longer needed big teeth可以推断，在下巴出现之前， 人类的牙齿较大。

4. C.细节理解题。根据倒数第三段中 的 My guess is that it most likely happened around two million years ago 可命，Pampush博士认为下E最可能 出现在约二百万年前。

5. B.篇章结构题。划线部分指代前一 句中的 the chin was an example of sexual selection,with attractive chins marking out men who are likely to make good mates ,由此可知〜the theory 指代“下巴帮助男性找到好配偶”这一 说法。