文章內容不難。但是要仔細看懂，不能偷懶。
For years, the leading theory for what caused the Younger Dryas (a dramatic reversal, about 12,900 years ago, in a global warming trend) was a release of water from Glacial Lake Agassiz. The theory posited that this meltwater flooded into the North Atlantic, lowering the salinity and intensity of surface waters enough to prevent them from sinking. Ocean currents were changed in such a way that northward transport of heat in the ocean diminished, and the North Atlantic regions plunged back into near-glacial conditions. However, evidence has emerged that the Younger Dryas began long before freshwater flooded the North Atlantic. Additionally, the temperature changes induced by a shutdown in the North Atlantic heat conveyor system are too small to explain the Younger Dryas.
1. The author of the passage implies which of the following about the release of water from glacial Lake Agassiz?
A. The notion that the release occurred has been challenged by more recent findings.
B. The release probably occurred much earlier than scientists have generally assumed.
C. The release would not have been sufficient to cause any temperature change in the North Atlantic.
D. The timing of the release is such that it probably did not trigger the onset of the Younger Dryas.
E. The release was probably unrelated to the global warming trend that was taking place.
答案：D
2. The passage is primarily concerned with
A. presenting evidence that undermines an explanation
B. explaining the nature of a climatological phenomenon
C. questioning the timing of a particular event
D. discussing a new explanation for a phenomenon
E. suggesting revisions to a popular theory
答案：A
解析見下。
For years, the leading theory for what caused the Younger Dryas (a dramatic reversal, about 12,900 years ago, in a global warming trend) was a release of water from Glacial Lake Agassiz.
第1句：多年來，對什麼造成了新仙女木期（大約12,900年前，在一個全球變暖趨勢中的戲劇性的逆轉）的主流理論是從阿加西斯冰川湖中釋放出來的水。
這句話告訴我們，首先存在【全球變暖趨勢】。
接著，在這個趨勢之中，存在一個戲劇性的逆轉——叫它戲劇性的，顯然是因為要麼逆轉的幅度大，要麼逆轉得很突然，跟演戲似的。這個逆轉叫做新仙女木期。既然它是對變暖趨勢的逆轉，那它一定就是溫度的突然降低。
問題：什麼造成了新仙女木期？——什麼造成了在一個全球變暖趨勢中的某一段時間的溫度突然降低？
the leading theory，也就是一個主流理論，認為是【從阿加西斯冰川湖中釋放出來的水】造成了溫度降低。
The theory posited that this meltwater flooded into the North Atlantic, lowering the salinity and intensity of surface waters enough to prevent them from sinking.
第2句：這個理論認為，這種融水湧入了北大西洋，降低了表層水的鹽度和強度，足以防止它們下沉。
【冰川湖】的融水應該是淡水，北大西洋的海水是鹽水。淡水衝入鹽水，降低了北大冰洋的表層水的鹽度和強度。表層水相對下層水變輕了，就沉不下去了。
Ocean currents were changed in such a way that northward transport of heat in the oceandiminished, and the North Atlantic regions plunged back into near-glacial conditions.
第3句：洋流發生了變化，以至於海洋向北傳輸的熱量減少，北大西洋地區又回到近冰期的狀態。
海洋中存在洋流——也就是，看起來是一汪平靜的海水，實際上內部存在水流，不斷運動。這就叫洋流。原本的洋流運動被上述的【表層水相對下層水變輕了，就沉不下去了】的現象改變了。原先的洋流運動是會造成【海洋向北傳輸熱量】的。現在洋流改變，這種向北傳輸的熱量減少了，造成北邊變冷了——北大西洋地區又回到近冰期的狀態。
However, evidence has emerged that the Younger Dryas began long before freshwater flooded the North Atlantic.
第4句：然而，有證據出現表明，新仙女木期在淡水湧入北大西洋之前很久就開始了。
按照老理論的看法，是因為淡水湧入北大西洋，導致了北邊變冷，造成了新仙女木期。
但是，問題來了。新證據出現了，表明在淡水湧入之前，新仙女木期早就開始了——也就是氣候早就變冷了。
這說明老理論不對。
Additionally, the temperature changes induced by a shutdown in the North Atlantic heat conveyor system are too small to explain the Younger Dryas.
第5句：此外，由於北大西洋熱傳輸體系停運引起的溫度變化太小，不足以解釋新仙女木期。
另外，老理論的意思是，是淡水湧入，使北大西洋熱傳輸體系效率變低，所以變冷了。
但這個理論除了上面所說的時間對不上以外，還有一個漏洞：北大西洋熱傳輸體系哪怕是停運了，能引起的溫度改變也很小，和新仙女木期巨大的溫度變化對不上。
綜上：文章是在diss舊理論。老的理論認為，出現新仙女木期是因為淡水融化湧入。作者通過講了兩個漏洞（首先，水的融化晚於新仙女木期；其次，水的融化引發的溫度變化不大，不足以解釋新仙女木期的出現），向讀者說明：舊理論基本站不住腳啦。
第一題解析略。需要請留言。
2. The passage is primarily concerned with
本文主要關注
A. presenting evidence that undermines an explanation
A.提出破壞一個解釋的證據
為了推翻老解釋，文章提出了證據。A對。
看錯誤選項。
B. explaining the nature of a climatological phenomenon
B.解釋一個氣候現象的性質
明明是在解釋它為什麼發生。
C. questioning the timing of a particular event
C.質疑一個特定事件的時間
沒質疑新仙女木期發生的時間。
D. discussing a new explanation for a phenomenon
D.討論一個現象的新解釋
根本沒有提出新解釋。
E. suggesting revisions to a popular theory
E.建議修訂一個流行的理論
沒建議修訂舊理論。幾乎直接推翻了它。
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