[解析]
(1)细节理解题。根据第三段中In 1981,the entire species around the world was down to the seven crested ibises which were found only in Yangxian County,northwest China's Shaanxi Province,and deep in the Qinling Mountains,making Qinling,a natural boundary between China's north and south,the last shelter of the wild birds.(1981年,全世界的朱鹮只剩下7只,这些朱鹮只在中国西北陕西省阳县和秦岭深处发现,作为中国南北自然分界线的秦岭成为了野生朱鹮最后的避难所。)可知,之所以秦岭对朱鹮来说是重要的,是因为这里曾经是朱鹮最后的栖息地。故选B。
(2)推理判断题。根据第四段中Since 1981,the local government of Yangxian County has put forward four bans for the protection of the species,prohibiting activities including hunting in the birds' living areas,cutting down trees where they nest,using chemicals in their food﹣finding areas,and firing guns in their breeding(繁殖)areas. (自1981年以来,阳县当地政府提出了四项保护物种的禁令,禁止在鸟类的生活区狩猎,砍伐它们筑巢的树木,在它们寻找食物的区域使用化学物质,以及在它们的繁殖区开枪。)可知,本段介绍的是政府在拯救朱鹮方面起着关键作用。故选D。
(3)推理判断题。根据最后一段中"It is lucky that the crested ibis,an ancient bird,is still flying around," said Zan Linsen("幸运的是,朱鹮这种古老的鸟类还在飞来飞去,"赞林森说。)可知,赞林森认为,很幸运能够看到这种古老的鸟儿还能飞来飞去,因此推断这让赞林森感到高兴和宽慰。故选B。
(4)最佳标题题。根据第一段From the world's last seven to a global population of more than 5,000,China spent nearly 40 years bringing back crested ibises(朱鹗)from the edge of extinction.(从世界上最后的7只到全球5000多只,中国花了近40年的时间将朱鹮从灭绝的边缘救了回来。)以及倒数第二段中Years of constant effort have brought promising results.It is estimated that there are more than 5,000 crested ibises in the world now,and a majority of them live in Shaanxi.The bird's habitat in China has risen from less than 5 square km in 1981 to the current 15,000 square km.(多年来的不懈努力取得了可喜的成果。据估计,目前世界上有5000多只朱鹮,其中大部分生活在陕西。这种鸟在中国的栖息地从1981年的不到5平方公里增加到现在的1.5万平方公里。)可知,文章介绍的是这篇文章主要讲述了中国在近40年的努力下,成功将朱鹗这一濒临灭绝的物种从全球仅剩的7只增加到超过5000只。多年的努力带来了显著成果。C选项"Endangered crested ibises making a comeback(濒危朱鹮不断回归)"概括文章主要内容,为最佳标题。故选C。