今天，前程百利小编为大家分享的托福听力讲座中环境科学类文章，这篇文章来自于《美国科学人60秒》。主要讲的是阿拉斯加的绝大多数冰山融化，造成海平面上升。但是融化的冰块一般都是在陆地上的冰块。大家可以参考一下，为大家积累背景知识，攻克托福听力高分。
The vast majority (绝大部分)of ice loss in Alaska glaciers comes from those that sit completely on land—which contributes melt water to sea level rise.
本段是文章的主旨段概括了本文的中心思想：阿拉斯加在陆地上的冰川开始融化，造成海平面上升。这就相当于托福听力讲座中的第一题，本段一定会出一个主旨题。这样分析才能更加符合ETS的出题逻辑。
The world’s mountain glaciers contain just 1 percent of all the ice on Earth. But their rapid melting accounts for about a third of recent sea level rise. Most of these glaciers—that start and end on land—shrink away through gradual surface melting. But others, known as tidewater glaciers(入海冰川), flow out into the sea. And by calving(冰解) off massive icebergs, these glaciers can collapse in the blink of an eye, geologically speaking.
这段主要说的是山地冰川只包含地球1%的水，但是但却对海平面上升做了三分之一的贡献。这里容易出细节题。尤其是but后面的内容是重点。
For example, the Columbia Glacier in Alaska’s Chugach Mountains, is a tidewater glacier that once filled a long fjord. It’s retreated 12 miles in just the last 25 years.
本段为大家举了个例子，运用举例原则，这里也会是讲座考点之一。信号词为For example.
Shad O’Neel: “So this tiny little glacier in Alaska is capable of producing 1 percent of the sea level rise budget(预算). And so we know that individual calving glaciers can do crazy things and can act really dramatically and can have this rapid response.”Scientists thought that tidewater glaciers, because of their unstable behavior, might be an important source of the torrent (奔流)of melt water flowing out of Alaska and northwest Canada, where ice has been disappearing at especially alarming rates. But all mountain glaciers, tidewater and otherwise, are notoriously(众所周知的) hard to quantify(量化).
本段主要讲的是冰川不断的消失。So和but都是信号词，不仅是记笔记的重点，而且是考点，所以这些地方要引起大家的注意。
The results surprised them: Tidewater glaciers accounted for just 6 percent of the region’s total ice loss. The vast majority came from surface melting of glaciers that sit completely on land.
本段的意思是说经结果显示融化的冰川主要是来自地面冰川。The results surprised them，这是考点的信号词。
所以大家在备考托福听力的过程中要注意整篇文章的逻辑关系以及段与段的逻辑关系，以及句子内部的关系。而且要注意考点的信号词，这样才能把握重点有针对性的听，才能搞定托福听力。
好了以上就是前程百利小编为大家整理的托福听力环境科学背景材料分析，希望能在备考的路上祝大家一臂之力。最后，小编预祝大家在托福考试中取得好成绩。
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