When a dog looks at you with big puppydog eyes, it's hard for you to go away, and you may speak out “Awww” without hesitation. However, there's a reason why you find a dog's stare so attractive. That sweet stare actually causes the release of a particular hormone, or chemical messenger in the body. This hormone creates feelings of affection in humans. The same thing happens to dogs when people look back at them. Scientists believe this helps people and their fourlegged friends bond, or feel connected. Scientists have wondered what causes dogs to lovingly stare at their owners. To find out, a team of researchers from Azabu University in Japan studied 30 owners and their dogs.
The researchers found that after the pets and their owners spent half an hour together, both showed a rise in oxytocin (催产素). One key role of this hormone in many animals is to promote bonding, like that between a mother and newborn. The increase of oxytocin didn't happen, though, when scientists repeated the experiment with wolves and the humans who had raised them.
A second experiment also found that if dogs were given oxytocin, they looked at their owners longer. Scientists aren't sure exactly why, but this reaction occurred only with female dogs. Their owners' oxytocin levels also rose as a result.
The result of these experiments might help answer an ageold question: How did the fearsome wolf ancestor of modern dogs turn into man's best friend? Takefumi Kikusui, an animal scientist who worked on the study, thinks that the_change happened when dogs first became domestic (驯养的)．
According to Kikusui, there may have been a small group of wild dogs that were naturally friendlier. “Humans are very sensitive to eye contact. By using this special communication tool, the dogs are able to win over our hearts. If they are more likely to make eye contact, it would be easier for them to bond with dog owners，” Kikusui said.
本文是一篇应用文。主要叙述科学家解开了狗与人类的关系演变成今日如此这般和谐的原因之谜。
1．According to Paragraph 1, people say “Awww” to ________.
A．make the dog stare at them
B．express their love for the dogs
C．draw the dogs attention away
D．warn the dogs not to approach them
答案：B
解析：推理判断题。第一段开头When a dog looks at you with big puppydog eyes, it's hard for you to go away, and you may speak out “Awww” without hesitation. However, there's a reason why you find a dog's stare so attractive.当狗看着你，你毫不犹豫地说“Awww”，不愿意离开。这是因为你觉得狗的注意力很有吸引力，狗吸引了你，说明你爱狗。故选B项。
2．According to the passage, oxytocin can ________.
A．reduce animals' pain of giving birth
B．motivate animals' desires to protect others
C．help animals to develop a better relationship with their owners
D．enable animals to survive more easily from dangers
答案：C
解析：细节理解题。第二段开头的．..after the pets and their owners spent half an hour together, both showed a rise in oxytocin (催产素). One key role of this hormone in many animals is to promote bonding……宠物和主人在一起半个小时，人与狗身上的催产素就会增加了。这种激素在许多动物中的关键作用就是促进关系。说明催产素可以帮助动物加强与主人的联系，提升他们之间的关系。故C项正确。
3．The underlined words “the change” in Paragraph 4 refer to that ________.
A．dogs became friends with humans
B．wolves begin to bond with humans
C．dogs and wolves are best friends
D．dogs were domesticated by humans
答案：A
解析：推理判断题。第三、四两段给狗催产素，它们注视主人时间更长。但是只有母狗会如此，所以给狗催产素后，狗的反应不一样。这些实验的结果可能有助于解决一个古老的问题：现代狗是如何变成人类最好的朋友的？从事这项研究的动物科学家Takefumi Kikusui认为，这种变化就是狗最初成为家畜时发生的变化。由此可推断出，这种变化就是狗由令人害怕的狼祖先变成人类最好的朋友。分析选项可知A正确。
4．What's the purpose of the passage?
A．To call on humans to be friendly to dogs.
B．To give advice on how to get along with dogs.
C．To introduce the evolution process of wild dogs.
D．To explain why humans and dogs are connected.
答案：D
解析：写作意图题。通读全文可知，本文解释了狗与人类的关系如何演变成今天的如此和谐的朋友关系的原因。分析选项可知D项(解释人类和狗联系的原因)符合题意，故选D项。
