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(馴化) 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(永凍層) 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(標本) 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

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.”

　 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(永凍層) 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.

　 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.”

68. The first humans into the New World brought dogs along with them because dogs　　　　 .

　 A. kept people company B. were easy to stay alive

C. helped protect the supplies D. offered excellent service

69. The underlined word “remains” in Paragraph 3 probably refers to 　　　　　.

　 A. dead bodies B. animal waste　　 　 C. leftover food　 　　 D. living environment

70. According to the study described in Paragraph 3, 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 studied were not from dogs brought by Europeans

D. the bones found by the gold miners were from American wolves

71. The passage mainly talks about 　　　　　.

　 A. the DNA study of dogs in NorthAmerica 　

B. the origin of the North American dogs

C. why ancient people brought dogs to America 　

D. the difference between Asian and American dogs

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(馴化) 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(永凍層) 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(標本) 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. 1.

   The underlined word “remains” is closed in meaning to ______

   1. A.
      leftover food
   2. B.
      animal waste
   3. C.
      dead bodies
   4. D.
      living environment
2. 2.

   According to the study described in Paragraph 4, we can learn that ______

   1. A.
      ancient dogs entered North America between 1450 and 1675 AD
   2. B.
      the 11 bones of ancient dogs are not from native American dogs
   3. C.
      the bones discovered by the gold miners were from North American wolves
   4. D.
      the bones studied were not from dogs brought into North America by Europeans
3. 3.

   What can we know from the passage?

   1. A.
      Native Americans domesticated local wolves into dogs
   2. B.
      Scientists discovered some ancient dog remains in 1920s
   3. C.
      Latin America’s dogs are different from North America’s in genes
   4. D.
      Ancient dogs entered North America across the Bering Land Bridge
4. 4.

   The first humans into the New World brought dogs along with them because ______

   1. A.
      dogs fed on mice
   2. B.
      dogs were easy to keep
   3. C.
      dogs helped protect their resources
   4. D.
      dogs could provide excellent service
5. 5.

   What does the passage mainly talk about ______

   1. A.
      the origin of the North American dogs
   2. B.
      the DNA study of ancient dogs in America
   3. C.
      the reasons why early people entered America
   4. D.
      the difference between Asian and American dogs

Dear Parents of the Class of 2015.

On behalf of the University, we would like to invite you to attend Freshman Parents Weekend, which will take place Friday-Sunday, Oct. 14-16, 2011.

Freshman Parents Weekend is designed to introduce you to some of the most important aspects of undergraduate life at Princeton. Panel discussions, lectures and presentations will provide you with opportunities to hear from and ask questions of administrators（管理者）, staff and cllege students who are familiar with the academic, campus life and residential（住校）experiences of our newest students. Open houses, tours, presentations, and cultural and athletic events will allow you to experience many of the activities Princeton students value and enjoy.

Just as important as the formal program is the opportunity for your sons and daughters to share their excitement about their lives as they spend time with you, introduce you to their friends and show you around the campus.

Please use the online registration form to let us know whether you will be able to come to Princeton for Freshman Parents Weekend. If you prefer to print the form to fill out, please submit the completed form no later than Wednesday, Oct. 5.

Should you have questions or want further information, please contact Lucy Weise at the Office of Conference and Event Services at (609) 258-1741, or email lweise@princeton.edu.

       We do hope you will be able to join us, and we look forward to meeting you.

Sincerely,

Valerie Smith, Dean of the College

Cynthia Cherrey, Vice President for Campus Life

44．Where can you possibly read this text?

       A．In a newspaper.                                   B．On a web page.

       C．In a textbook.                                      D．In a magazine.

45．The purpose of the writer is to         .

       A．tell how to use the online registration from

       B．announce a weekend event for freshmen and a formal inhibition

       C．introduce some useful information about the life at Princeton

       D．invite freshmen’s parents to attend Freshman Parents Weekend

46．After filling out the printed form, what should the parents do?

       A．Present it on time.                                                               B．Contact Lucy Weise

       C．Write a letter to their children.               D．Obey the rules of the activities.

47．The activities in Freshman Parents Weekend can’t be learned through         .

       A．contacting Lucy Weise at (609) 258-1741

       B．reading Paragraph 4 and Paragraph 6

       C．reading Paragraph 2 and Paragraph 3

       D．emailing lweise@princeton.cdu