Now listen to part of a lecture on the topic you just read about.現(xiàn)在來聽一段有關(guān)你剛剛聽到的話題的演講 。Quackers are certainly a very strange phenomenon.嘎嘎聲肯定是一個非常奇怪的現(xiàn)象。Experts still debate what the source of the sound was.專家們還在爭論聲音的來源是什么。No one can be sure exactly what caused them.沒有人能確定到底是由什么引起的。But these experts cite certain problems with all of the theories that you just read about.但這些專家引用一些問題以及所有你讀到的理論。Here are a few of the arguments that they made.這里有一些他們的論點。First, the idea that the sounds were caused by Orca whales seems plausible at first but is ultimately highly unlikely.首先，這個聲音是由虎鯨引起的，咋一聽來是可信的，但最終是極不可能的。It's true that there are Orca populations in the general areas that the Russian submarines were patrolling.的確，虎鯨群出沒在俄羅斯?jié)撏а策壍膮^(qū)域。But Orca whales mostly live near the surface of the water.但虎鯨鯨主要住在水面附近。The submarines typically remain deep in the ocean and should not have been able to hear the whale sounds from near the surface.潛艇通常保持在海洋深處，不應(yīng)該能夠聽到鯨魚從海面發(fā)出的聲音。Also the Orca whales would have been detected by the Russian sonar if they were nearby.而且虎鯨會被俄羅斯聲納探測到，如果它們在附近。Giant squid may be a better candidate but one critical fact speaks against this squid theory as well.巨型烏賊可能是一個更好的候選者，但也有一個關(guān)鍵的事實反對這個烏賊理論。Russian submarines first detected quacker sound in the 1960s and reports of them continued for about two decades.1960年代，俄羅斯?jié)撏状翁綔y到嘎嘎聲，有關(guān)這份報告持續(xù)了約二十年。But the sounds disappeared entirely by the 1980s.但在1980年代的聲音完全消失了。However, as far as we know, squid have always lived in the ocean where the submarines were patrolling and continue to live there today.然而，據(jù)我們所知，魷魚一直住在潛艇的海洋巡邏的區(qū)域，今天仍住在那里。If these were squid sound, there would be no reason to suddenly start hearing them in one decade and then suddenly stop hearing them twenty years later.如果這些是烏賊的聲音，就沒有理由在其中一個十年突然聽到它們的聲音，然后突然在之后的二十年聽不到它們的聲音了。Third, the idea that the quackers were caused by a secret submarine from another country does not hold up.第三，嘎嘎聲是由別的國家的秘密潛艇所引起的，這一想法是站不住腳的。The sources of the sound appear to move around and change direction very quickly.聲音的來源似乎很快移動和改變方向。Submarines cannot move or change direction that quickly.潛艇不能那么快移動或改變方向。Also all submarines make some engine noise.而且所有潛艇能引起一些引擎噪音。But no such noise accompanied the quackers.但是沒有一種噪音會伴隨著嘎嘎聲。Even today, we don't have the technology to build submarines that are that fast and have engines that are that silent.即使在今天，我們沒有技術(shù)建造速度那么快的潛艇和靜音引擎
