[解析]
(1)段落大意题。根据第三段 The paper says the paddlefish was announced extinct for two reasons.(报纸上说白鲟被宣布灭绝有两个原因。)和下句It said that the fish was not able to survive because of widespread overfishing and damage to its native environment in the Yangtze River.(报道称,由于过度捕捞和对长江原生环境的破坏,这种鱼无法存活。)可知第三段内容为白鲟的灭绝原因。因此D.The reasons for the Chinese paddlefish's extinction.(中国白鲟灭绝的原因。)符合题意。故选D项。
(2)推理判断题。由第四段The extinction of the Chinese paddlefish was "a huge loss" to nature.(中国白鲟的灭绝是大自然的"巨大损失"。)和最后一段"Humans should not live alone on this planet, " the user added("人类不应该独自生活在这个星球上,"用户补充道)可知,在过去的几十年里,由于人类的活动,长江的生态几乎处于崩溃状态。中国已采取措施改善长江的环境,正如网友补充说的,人类不应该独自生活在这个星球上。所以最能描述长江的现状的是"对长江环境的拯救改善,保护长江的生态就是保护人类自身"。A.To protect animals is to protect humans.(保护动物,就是保护人类);B.It's never too late to mend.(改过迁善从不嫌晚);C.Well begun is half done.(良好的开端是成功的一半);D.No pain,no gain.(一分耕耘,一分收获)。故选D项。
(3)观点态度题。根据文章第一段The Chinese paddlefish(白鲟)﹣one of the world's largest freshwater fish﹣has been announced extinct(中国白鲟﹣﹣﹣世界上最大的淡水鱼之一﹣﹣﹣已经被宣布灭绝)和第二段But a research paper recently published in Science of the Total.Environment reported the paddlefish was now extinct(但是最近发表在《总体科学》上的一篇研究论文。环境报告称白鲟现已灭绝)两次提到中国白鲟灭绝了;第四段The extinction of the Chinese paddlefish was "a huge loss" to nature.(中国白鲟的灭绝是大自然的"巨大损失"。)可知作者的态度很痛心,"震惊"。A.Excited.兴奋的;B.Shocked.震惊的;C.Satisfied.满意的;D.Happy.高兴的。故选C项。
(4)标题归纳题。文章第一段提及中国白鲟被宣布灭绝,并描述了中国白鲟的形态特征以及历史,第二、三、四段是中国白鲟研究小组的人员组成,以及研究的内容和结果。最后三段则是关于中国政府以及中国媒体、网民对此事的反应。所以最佳标题是"中国白鲟被宣布灭绝"。因此C.The Chinese Paddlefish has been Announced Extinct(中国白鲟已经被宣布灭绝)是本文的最佳标题。故选C项。