Now listen to part of lecture on the topic you just read about.现在来听一段有关你刚刚阅读到的话题的演讲 。Well, ongoing investigations have revealed that predation is the most likely cause of sea otter decline after all.持续的调查研究显示，掠食终究是海獭减少最可能的原因。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，污染理论被没有人能真正找到被冲上阿拉斯加海滩的死海獭这个事实所弱化。That's not what you would expect if infections caused by pollution started killing a lot of otters.如果污染所引起的传染病开始杀死许多海獭的话，你看到的不会是这种情况。On the other hand, the fact that it's so hard to find dead otters is consi
