题目

American black bears appear in a variety of colors despite their name. In the eastern part of their range(地理分布区), most of these bears have shiny black fur, but in the west they grow brown, red or even yellow coats. To the north, the black bear is actually gray or white. Even in the same litter(窝), both brown and black furred bears may be born.     Black bears are the smallest of all American bears, ranging in length from 5 to 6 feet, weighing from 300 to 500 pounds. Their eyes and ears are small and their eyesight and hearing are not as good as their sense of smell. Lik有学者指出，中国此时期（宋朝）的航海科技是领先全世界的。中国造的有分舱区的大船——包含四层甲板、四或六桅……航海图用罗盘导向，这种科技远远超过西亚与欧洲。当时造船业发达的地区是A. 广州B. 杭州C. 景德镇D. 开封