Question

【题目】阅读短文，完成下列问题。
A
When people first walked across the Bering Land Bridge thousands of years ago, dogs were by their sides, according to a study published in the journal Science.
Robert Wayne of the University of California, Los Angeles, and Jennifer Leonard of the Smithsonian Institute, used DNA material—some of it unearthed by miners in Alaska—to conclude that today's domestic dog originated in Asia and accompanied the first humans to the New World about 10,000 to 15,000 years ago. Wayne suggests that man's best friend may have enabled the tough journey from Asia into North America. “Dogs may have been the reason people made it across the land bridge,” said Wayne. “They can pull things, carry things, defend you from fierce animals, and they're useful to eat.”
Researchers have agreed that today's dog is the result of the domestication(驯化) of wolves thousands of years ago. Before this recent study, a common thought about the precise origin of North America's domestic dog was that Natives domesticated local wolves, the descendents(后代) of which now live with people in Alaska, Canada, and the Lower 48.
Dog remains from a Fairbanks-area gold mine helped the scientists reach their conclusion. Leonard, an evolutionary biologist, collected DNA from 11 bones of ancient dogs that were locked in permafrost(永冻层) until Fairbanks miners uncovered them in the 1920s. The miners donated the preserved bones to the American Museum of Natural History in New York City, where they remained untouched for more than 70 years. After borrowing the bones from the museum, Leonard and her colleagues used radiocarbon techniques to find the age of the Alaska dogs. They found the dogs all lived between the years of 1450 and 1675 A.D., before Vitus Bering and Aleksey Chirikov who were the first known Europeans to view Alaska in 1741. The bones of dogs that wandered the Fairbanks area centuries ago should therefore be the remains of “pure native American dogs,” Leonard said. The DNA of the Fairbanks dogs would also expose whether they were the descendents of wolves from North America.
Along with the Fairbanks samples, the researchers collected DNA from bones of 37 dog specimens(标本) from Mexico, Peru, and Bolivia that existed before the arrival of Columbus. In the case of both the Alaska dogs and the dogs from Latin America, the researchers found that they shared the most genetic material with gray wolves of Europe and Asia. This supports the idea of domestic dogs entering the New World with the first human explorers who wandered east over the land bridge.
Leonard and Wayne's study suggests that dogs joined the first humans that made the adventure across the Bering Land Bridge to slowly populate the Americas. Wayne thinks the dogs that made the trip must have provided some excellent service to their human companions or they would not have been brought along. “Dogs must have been useful because they were expensive to keep,” Wayne said. “They didn't feed on mice; they fed on meat, which was a very guarded resource.”
（1）The underlined word “remains” is closed in meaning to ______.
A.leftover food
B.animal waste
C.dead bodies
D.living environment
（2）According to the study described in Paragraph 4, we can learn that ______.
A.ancient dogs entered North America between 1450 and 1675 AD
B.the 11 bones of ancient dogs are not from native American dogs
C.the bones discovered by the gold miners were from North American wolves
D.the bones studied were not from dogs brought into North America by Europeans
（3）What can we know from the passage?
A.Native Americans domesticated local wolves into dogs.
B.Scientists discovered some ancient dog remains in 1920s.
C.Latin America's dogs are different from North America's in genes.
D.Ancient dogs entered North America across the Bering Land Bridge.
（4）The first humans into the New World brought dogs along with them because ______.
A.dogs fed on mice
B.dogs were easy to keep
C.dogs helped protect their resources
D.dogs could provide excellent service
（5）What does the passage mainly talk about ______.
A.the origin of the North American dogs
B.the DNA study of ancient dogs in America
C.the reasons why early people entered America
D.the difference between Asian and American dogs

Answer 1

【答案】
（1）C
（2）D
（3）D
（4）D
（5）A
【解析】本文以追踪北美狗的起源为线索，通过数据和研究等说明了其起源。
（1）C猜测词义题。从文中collected DNA from 11 bones of ancient dogs可知，科学家从古代狗的11块骨头中提取DNA，所以remains此处为尸体的意思，故选D。
（2）D细节理解题。根据文章第四段最后两句The bones of dogs that wandered the Fairbanks area centuries ago should therefore be the remains of “pure native American dogs,” Leonard said. The DNA of the Fairbanks dogs would also expose whether they were the descendents of wolves from North America.可知，古代狗的骨头几个世纪之前分布在费尔班克斯地区，因此应该是纯种的美国狗的遗骨。这些狗的DNA也会揭示它们是否是北美狼的后代。而且前面提到，它们存在时期比第一批去那的欧洲人要早，所以不可能是被欧洲人带入北美的。由此可知D项正确。
（3）D细节理解题。根据第六段第一句Leonard and Wayne's study suggests that dogs joined the first humans that made the adventure across the Bering Land Bridge to slowly populate the Americas.可知D项说法正确。
（4）D细节理解题。根据文章第六段第二句Wayne thinks the dogs that made the trip must have provided some excellent service to their human companions or they would not have been brought along.可知，狗一定是给人类伙伴提供了很出色的服务的，否则他们不会被带去。由此可知D正确。
（5）A主旨大意题。文章是以北美狗的起源为线索开展全文的，可知A项说法正确。