Where do dogs come from? Gray wolves are their ancestors. Scientists are pretty consistent about that. And researchers have suggested that dogs' origins can date back to Europe, the Near East, Siberia and South China. Central Asia is the newest and best candidate, according to a large study of dogs from around the world. Laura M. Shannon and Adam R. Boyko at Cornell University, and an international group of other scientists, studied not only purebred dogs, but also street or village dogs. Dr. Shannon analyzed three different kinds of DNA, Dr. Boyko said, the first time this has been done for such a large and diverse group of dogs from 38 countries. And that led them to Central Asia as the place of origin for dogs in much the same way that genetic studies have located the origin of modern humans in East Africa. The analysis, Dr. Boyko said, pointed to Central Asia, as the place where "all the dogs alive today" come from. The data did not allow precise dating of the origin, he said, but showed it occurred at least 15,000 years ago. Greger Larson of Oxford University, who is leading a large international effort to analyze ancient DNA from fossilized bones, said he was impressed by the study. "It's really great to see not just the number of street dogs, but also the geographic breadth and the number of remote locations where the dogs were sampled," he said in an email. He also praised the sampling of different kinds of DNA and the analytic methods. Dr. Larson, who was not involved with the study, said he thought the Central Asia finding required further testing. He said he suspected that the origins of modern dogs were "extremely messy" and that no amount of sampling of living populations will be definitive. He said a combination of studies of modern and ancient DNA is necessary. According to the research on a large number of dogs, we can know _ . A) dogs mainly lived in Europe and the Far East B) dogs would like to live in Central Asia C) dogs' ancestors come from gray wolves D) the Near East has many gray wolves
C
(Question)
I will never forget the lesson about my window. Four years ago, I moved to a house in a large town. One of my new neighbors' house was only a few feet away from mine. There lived a woman. Through one of my windows, I could see her reading by her window every afternoon. Several months later, I found I couldn't see the woman clearly. I thought her window was too dirty. I said to myself, "Why doesn't she clean her window? It looks terrible!" One afternoon, I decided to clean my house including the window. I felt tired after three hours of hard work. So I sat down by the window for a rest. What a surprise! I could see the woman reading there clearly again! By that time, I realized that my own window was too dirty, not hers! I really felt _ for myself. I had been watching her through my dirty window in the past days! The experience is very important for me. So I try to clean the window of my heart before judging others. The writer couldn't see the woman clearly because _ . A) the writer's window was dirty B) the woman's house was too far C) the woman didn't open her window D) there was something wrong with his eyes.
(Answer)
A
Ques: The snow has paralysed transport in China during the country's most important vacation period, the celebration of the Chinese New Year. Not only have transport delays hindered personal trips, but they have also slowed the delivery of fresh produce to markets. Consequently, in Zhengzhou, the capital city of the Henan province, tomato prices have doubled, and the cost of 47 other vegetables has increased by 36%, as reported by local media at the end of January. According to an inside PR source, "wholesalers in Beijing were quoted as saying that only about 20% of the usual fresh vegetable supplies were reaching the city." As an Asian country with a diet based on fresh produce, the shortage of vegetables and the rise in prices is not only affecting fresh food producers, but also the final consumers. In terms of production, this is the worst snow disaster to hit China in the last 50 years, affecting a total of 9.4 million hectares of farmland in the country, according to a report published on 4 February 2008 by Feng Tao of Xinhua News, at the Chinese government website. Most of the crops devastated by the frost are located in the middle and lower reaches of the Yangtze River, the traditional natural border between North and South China. Chen Xiwen, Director of the Office of the Central Leading Group on Rural Work, pointed out at the end of last week that "the blizzard disaster in the south has had a severe impact on winter crops, and the impact on fresh vegetables could be catastrophic in certain areas", as stated in the Xinhua News report. The Chinese government has been quick to take extreme measures. The Chinese Ministry of Agriculture (MOA) has sent 13 teams of experts to 8 of the areas most seriously affected by the harsh weather. The aim of this initiative is to provide farmers with technical assistance to minimize their losses. This passage mainly tells us _ . A) The snow in the south of China caused many problems. B) The effect of the snow in the south of China on the fresh food C) The snow in the south of China slowed the delivery of fresh produce to markets. D) The Chinese government has taken extreme measures to help the suffered farmers.
Ans: B
Here in Alaska, the wolf almost disappeared a few years ago, because hunters were killing hundreds of them for sport. However, laws were passed to protect the wolves from sportsmen and people who catch the animals for their fur. So the wolf population has greatly increased. Now there are so many wolves that they are destroying their own food supply. A wolf naturally lives on animals in the deer family. People there also hunt deer for food. Many of the animals have been destroyed by the very cold winters recently and by changes in the plant life there. When the deer can't find enough food, they die. If the wolves continue to kill large numbers of deer, the deer will disappear some day. And the wolves will, too. So we must change the life cycles there. If we killed more wolves, we would save them from starving. We also save deer and some farm animals. In another northern state, wolves attack cows and chickens for food. Farmers want the United States government to send a team of scientists to study the problem. They believe it is necessary to kill wolves in some areas and to protect them in places where there is a small population. Which of the following statements is true according to the passage? A) Some wolves in some areas must be killed, which others should be protected. B) Wolves should be protected, for there's a small population of it on earth. C) All wolves should be protected, for they eat deer, cows and chicken. D) It is necessary for scientists to protect wolves, or the cycle of life will be changed
A