評論
打印
Now listen to part of lecture on the topic you just read about.
現(xiàn)在來聽一段有關你剛剛閱讀到的話題的演講。
Well, ongoing investigations have revealed that predation is the most likely cause of sea otter decline after all.
持續(xù)的調查研究顯示，掠食終究是海獺減少最可能的原因。
First, the pollution theory is weakened by the fact that no one can really find any dead sea otters washing off on Alaskan beaches.
首先，污染理論被沒有人能真正找到被沖上阿拉斯加海灘的死海獺這個事實所弱化。
That's not what you would expect if infections caused by pollution started killing a lot of otters.
如果污染所引起的傳染病開始殺死許多海獺的話，你看到的不會是這種情況。
On the other hand, the fact that it's so hard to find dead otters is consistent with the predator hypothesis.
另一方面，很難找到死海獺的事實與獵食者假說一致。
If an otter is killed by a predator, it's eaten immediately so it can't wash up on shore.
如果海獺被其獵食者殺死，它會馬上被吃掉，所以不會被沖上岸。
Second, although orcas may prefer to hunt whales, whales have essentially disappeared from the area because of human hunters.
第二，雖然逆戟鯨更喜歡捕食鯨魚，但是鯨魚從這個地區(qū)消失本質上是因為人類捕獵者。
That means that orcas have had to change their diet to survive and since only smaller sea mammals are now available,
這意味著， 逆戟鯨為了生存必須改變它們的飲食，因為現(xiàn)在只有更小的海洋哺乳動物是可得到的，
orcas have probably started hunting those.
逆戟鯨可能已經開始捕食那些。
So it probably is the orcas that are causing the decline of all the smaller sea mammals mentioned in the passage — the seals, the sea lions and the sea otters.
所以，可能是逆戟鯨引起了文中所提到的小一點的海洋哺乳動物，海豹、海獅和海獺的減少。
And third, the uneven pattern of otter decline is better explained by the orca predation theory than by the pollution theory.
第三，捕獵假說比污染假說更好地解釋了海獺減少不均勻的方式。
What happens to otters seems to depend on whether the location where they live is accessible to orcas or not.
發(fā)生在海獺身上的事似乎取決于它們生活的地方是不是逆戟鯨能接近的地方。
In those locations that orcas can access easily, the number of sea otters has declined greatly.
在那些逆戟鯨很容易就能接近的地方，海獺的數(shù)量大大減少。
However, because orcas are so large, they can't access shallow or rocky locations.
然而，因為逆戟鯨太大了，它們不能接近淺水或者是多巖石的地方。
And shallow and rocky locations are precisely the types of locations where sea otter populations have not declined.
而淺水和多巖石的地方正是海獺的數(shù)量沒有減少的區(qū)域類型。
Summarize the points made in the lecture, being sure to explain how they respond to the specific points made in the reading passage.
總結演講中的觀點，準確解釋他們如何對文章中提出的觀點做出反應。
