（本文由海天教育供稿）
When prehistoric man arrived in new parts of the world, something strange happened to the large animals: they suddenly became extinct. Smaller species survived. The large, slow-growing animals were easy game, and were quickly hunted to extinction. Now something similar could be happening in the oceans.
That the seas are being overfished has been known for years. What researchers such as Ransom Myers and Boris Worm have shown is just how fast things are changing. They have looked at half a century of data from fisheries around the world. Their methods do not attempt to estimate the actual biomass (the amount of living biological matter) of fish species in particular parts of the ocean, but rather changes in that biomass over time. According to their latest paper published in Nature, the biomass of large predators (animals that kill and eat other animals) in a new fishery is reduced on average by 80% within 15 years of the start of exploitation. In some long-fished areas, it has halved again since then.
Dr. Worm acknowledges that these figures are conservative. One reason for this is that fishing technology has improved. Today’s vessels can find their prey using satellites and sonar, which were not available 50 years ago. That means a higher proportion of what is in the sea is being caught, so the real difference between present and past is likely to be worse than the one recorded by changes in catch sizes. In the early days, too, longlines would have been more saturated with fish. Some individuals would therefore not have been caught, since no baited hooks would have been available to trap them, leading to an underestimate of fish stocks in the past. Furthermore, in the early days of longline fishing, a lot of fish were lost to sharks after they had been hooked. That is no longer a problem, because there are fewer sharks around now.
Dr. Myers and Dr. Worm argue that their work gives a correct baseline, which future management efforts must take into account. They believe the data support an idea current among marine biologists, that of the 「shifting baseline」. The notion is that people have failed to detect the massive changes which have happened in the ocean because they have been looking back only a relatively short time into the past. That matters because theory suggests that the maximum sustainable yield that can be cropped from a fishery comes when the biomass of a target species is about 50% of its original levels. Most fisheries are well below that, which is a bad way to do business.
31. The extinction of large prehistoric animals is noted to suggest that
[A] large animals were vulnerable to the changing environment.
[B] small species survived as large animals disappeared.
[C] large sea animals may face the same threat today.
[D] slow-growing fish outlive fast-growing ones.
32. We can infer from Dr. Myers and Dr. Worm’s paper that
[A] the stock of large predators in some old fisheries has reduced by 90%.
[B] there are only half as many fisheries as there were 15 years ago.
[C] the catch sizes in new fisheries are only 20% of the original amount.
[D] the number of larger predators dropped faster in new fisheries than in the old.
33. By saying 「these figures are conservative」 (Line 1, Paragraph 3), Dr. Worm means that
[A] fishing technology has improved rapidly.
[B] the catch-sizes are actually smaller then recorded.
[C] the marine biomass has suffered a greater loss.
[D] the data collected so far are out of date..
34. Dr. Myers and other researchers hold that
[A] people should look for a baseline that can work for a longer time.
[B] fisheries should keep the yields below 50% of the biomass.
[C] the ocean biomass should be restored to its original level.
[D] people should adjust the fishing baseline to the changing situation.
35. The author seems to be mainly concerned with most fisheries』
[A] management efficiency.
[B] biomass level.
[C] catch-size limits.
[D] technological application.
名師解析
31. The extinction of large prehistoric animals is noted to suggest that
提及大型史前動物的滅絕是為了說明
[A] large animals were vulnerable to the changing environment.
大型動物容易受到環境變化的影響。
[B] small species survived as large animals disappeared.
當大型動物消失的時候小型物種存活了下來。
[C] large sea animals may face the same threat today.
大型海洋動物今天面臨相同的威脅。
[D] slow-growing fish outlive fast-growing ones.
成長緩慢的魚要比成長快速的魚活得長。
【答案】 C
【考點】 推斷題。
【分析】 通過題幹關鍵詞「大型史前動物的滅絕」可以定位到第一段。作者提到它們的滅絕是由於人類的捕殺，作者在第一段最後一句提到，「如今類似的事情可能會發生在海洋中」。因此可以得出結論，即，作者是為了引用大型史前動物的滅絕來引出海洋物種同樣面臨著由於人類過度捕撈而滅絕的這個話題，故正確答案是[C]。[A]、[B]、[D]選項都沒有能夠表達出作者的這個意圖，而只是很淺層去分析表象。
32. We can infer from Dr. Myers and Dr. Worm’s paper that
從邁爾斯博士
[A] the stock of large predators in some old fisheries has reduced by 90%.
一些老漁場裡大型捕食類魚種的貯存量已經減少了90%。
[B] there are only half as many fisheries as there were 15 years ago.
現在漁場的數量只有15年前數量的一半。
[C] the catch sizes in new fisheries are only 20% of the original amount.
新的漁場中的捕捉數量是原來數量的20%。
[D] the number of larger predators dropped faster in new fisheries than in the old.
新的漁場裡大型捕食類魚種的數目下降比舊的漁場快。
【答案】 A
【考點】 推斷題。
【分析】 根據題幹關鍵詞「Dr Myers and Dr. Worm’s paper」可以定位到第二段最後一句，「根據他們發表在《自然》雜誌上的最新論文，一個新的漁場在被開發後的15年中大型捕食類魚種的生物量平均減少了80%。在有些長期捕撈的地區，自那以後，這個數量又減少了一半。」本句的理解難點就是「In some long-fished areas, it has halved again since then.」這句話裡面的「since」從什麼時間開始計算，影響本題的解答。「since」指的是從15年結束後開始算呢，還是從15年的第一年開始算。如果是前者，則答案是[A]，因為新的平均下降80%，然後又下降了一半，這個意思就是一共下降了90%；如果是後者，則得出舊漁場大型捕食類魚種的減少速度低於新漁場，而且只有50%。「since」接時間，後面必須是一個時間點。如果「since」後面接的不是一個時間點而是時間段，則從該時間段結束的時候開始算。例句：「It has been 10 years since I lived in Beijing.」這句話的意思不是「我在北京十年了」，而是「我離開北京十年了」。因此本題的正確答案是[A]。「since」接的是15年結束後的那個點；而且這句話裡面還有一個很關鍵的詞「again」(再次)，也很明顯說明這裡指的是「在下降80%之後，又再次減少了一半」，即「餘下的20%又減少了一半，只剩下10%」。
33. By saying「these figures are conservative」(Line 1, Paragraph 3), Dr worm means that
[A] fishing technology has improved rapidly. 捕魚的技術已經得到快速提高。
[B] the catch-sizes are actually smaller than recorded. 捕魚量比實際記錄的少。
[C] the marine biomass has suffered a greater loss. 海洋生物量已經蒙受了更大的損失。
[D] the data collected so far are out of date. 目前收集的數據已經過時了。
【答案】 C
【考點】 推斷題。
【分析】 根據關鍵詞「conservative」的提示定位到第三段第一句。作者說「這個數據是保守的，因為捕魚的技術已經提高了。衛星和聲納定位儀都用上了。這就意味著現在海裡有更高比例的海洋生物被捕撈了。現在和過去的真正差異可能比通過捕撈記錄的反映出來的差異更要糟糕。」接下來的一句話的意思是「以前一些抓不住的海洋生物現在都可以抓住了，以前被鯊魚搶走的，現在由於鯊魚都不見了，自然被捕撈的就更多了。」作者同時提到，「由於以前的捕撈技術不夠先進，所以以前對海裡的生物的總量是低估的。」那麼我們可以得出這樣的結論「以前的海洋生物總量比我們當時估計的要高，而現在只剩下這麼一點了」，就是說「海洋物種被捕撈的比例遠遠超過我們的記錄」。因此可以得出[C]的結論。[A]項的錯誤在於「捕魚的技術已經得到快速的提高」這種提法僅僅是作者文中提到的一個原因，作者是為了用這個來證明有了這樣的科技，更多的海洋生物就被捕撈了，而不是為了說明技術得到提高。[B]試圖比較當時的捕撈量與記錄的差別。但是原文說的是今天和過去的真實差別比那個記錄反映出來的差別要嚴重的多。[D]的說法是沒有根據的。
34. Dr. Myers and other researchers hold that
邁爾斯博士以及其他一些研究人員堅持認為
[A] people should look for a baseline that can work for a longer time.
人們應該尋找一種能夠更長時間起作用的基準。
[B] fisheries should keep the yields below 50% of the biomass.
漁場應該將產量保持在生物量的50%以下。
[C] the ocean biomass should be restored to its original level.
海洋生物的數量應該恢復到原來的水平。
[D] people should adjust the fishing baseline to the changing situation.
人們應該根據變化的形勢調整捕魚數量的基準。
【答案】 D
【考點】 事實細節題。
【分析】 本題提到「Dr. Myers」和其他一些研究者的主張，題幹中用到了「hold」，而其近義詞就是「argue」，定位到最後一段第一句。「Dr. Myers」和「Dr. Worm」堅持認為「他們的工作是給出準確的捕撈數量基準，它是未來的管理工作必定要考慮的」，他們相信自己的數據支持了目前海洋生物學家的觀點，即「變化的底線」。也就是說，「人們應該根據變化的形勢調整捕魚數量的基準」，所以正確答案是[D]。[A]不正確的原因是文章中沒有提到持續時間更長，文章最後一段提到時間太短指的是調查研究的跨度年份很短。和基數沒有關係 [B]不是「Dr. Myers」堅持的主張，而是理論狀態下的海洋生物生產。[C]與原文的意思也不符合。
35. The author seems to be mainly concerned with most fisheries』
作者看上去主要關注大多數漁場的
[A] management efficiency. 經營效率。
[B] biomass level. 生物量水平。
[C] catch-size limits. 捕撈量的限制。
[D] technological application. 技術應用。
【答案】 B
【考點】 文章主旨題。
【分析】 本題問的是作者最關注的是漁場的哪一個方面，這個問題實際上考的是文章的主旨。從前到後，作者一直在提過度捕撈對海洋生物量的影響。[A]顯然不是本文的重點。[D]在文章中只是被作者引用來表示現在的海洋生物被過度捕撈。[C]在文中最後一段有提及，但是顯然不是文章的主題。作者最關心的是海洋生物量的變化，因此正確答案選[B]項。
難句解析：
1. That means a higher proportion of what is in the sea is being caught, so the real difference between present and past is likely to be worse than the one recorded by changes in catch sizes.
【結構分析】 本句是一個並列句，連接詞是「so」。前一個分句中，「that means」 後面省略了賓語從句連接詞「that」，在這個賓語從句中，「a higher proportion of what is in the sea」是主語，「is being caught」是謂語部分。這個主語裡面又包含了一個由「what」引導的從句，做介詞「of」的賓語。後一個分句是一個比較級結構，主語是「the real difference」，「the one」代替「the difference」，「recorded」是過去分詞做後置定語。
2. In the early days, too, longlines would have been more saturated with fish. Some individuals would therefore not have been caught, since no baited hooks would have been available to trap them, leading to an underestimate of fish stocks in the past.
【結構分析】 這裡是兩個句子。之所以把第一句拿來一起分析，是因為這句話的理解對第二句的理解很重要。第一句話中的「would have been more saturated」是虛擬語氣的一種，是對過去未能發生的事情的一種假設。隨後一句，仍然是虛擬語氣。我們來分析一下這個結構。「since」指的是原因，即，「當時怎麼就沒有這樣的可以裝誘餌的魚鉤」，其實際意思是「如果當初有這樣的魚鉤，一些海洋生物個體就不會被抓不住」。「leading」是現在分詞引導結果狀語。
3. The notion is that people have failed to detect the massive changes which have happened in the ocean because they have been looking back only a relatively short time into the past.
【結構分析】 本句的主句是「The notion is that…」，「that」引導表語從句。在這個表語從句中，「people have failed to detect the massive changes」是句子的主謂賓，「which」引導一個定語從句，指代「changes」。「because」引導一個原因狀語從句，在表語從句中表示原因。
4. That matters because theory suggests that the maximum sustainable yield that can be cropped from a fishery comes when the biomass of a target species is about 50% of its original levels.
【結構分析】 本句的主句是「that matters」，「because」引導一個原因狀語從句。在這個從句中，「theory suggests」是主句，「suggest」後面的「that」引導一個賓語從句。
全文翻譯：
當史前人類來到世界的各個新區域時，一些奇怪的事情也會發生在當地的大型動物身上。它們突然就滅絕了，較小的物種存活了下來。生長緩慢的大型的動物很容易成為獵物，很快被獵殺而滅絕。現在類似的情形也可能正在海洋中發生。
人們知道海洋被過度捕撈這個事實已經很多年了。邁爾斯博士
邁爾斯博士