尽管栖息地容易遭到破坏，但大天鹅仍以18万只的种群数量冠居天鹅家族之首，而且其栖息范围也超出了其他种类的天鹅。
With a population of about 180,000, the whooper, though vulnerable to loss of habitat, is among the most abundant of swans and trumps others in the sweep of its range.
据估，中国拥有2.5亿网络用户，网民数量居世界之首。
China has the world's largest online population of any country with an estimated 250 million users.
美国国家树木园内盆景收藏颇丰，其盆景数量和质量列于美国之首。
Quality and quantity of Penjing Collection of USNA rank first in United States of America.
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