在之前的文章中，有为考生们讲解过地理地质学的内容，在本篇，我们进一步来研究一下地球环境学科。前者往往和化学以及考古学有所交叉，后者的内容更接近我们的实际生活或认知，比如环境变化。当然也会涉及到许多场景词汇，广大考生在备考过程中还是要认真复习备考。今天带领大家具体看一下地球环境学类的听力段子应该如何应对。
一、概述
这一学科要求考生们要关注一些时事，并且扩大自己知识面，开拓视野，可以和地理地质学科一起关注。
☆大气环境，例如赤道无风带，大气环流，全球气候变化。
☆地面环境，例如风能，地下水的研究与保护。
☆海洋环境，例如海底热液，潮汐能。
☆其他话题，可能和天文学，生物学，地理地质学等产生交叉。
在此，考生最好能积累背景知识，多浏览一些原汁原味的报刊杂志，比如Scientific Americans、National Geographical等等，多积累相关词汇，熟悉发音。当然，刚才也提到了，新托福听力段子所涉及的话题往往千变万化且有所交叉，考生在熟悉背景知识的同时也要打牢基础，培养快速辨音能力和短时记忆能力，才能以不变应万变。
二、案例分析
请看一个地球环境学的经典案例：
E.G.TPO17 Milankovitch Hypothesis
听力原文：
1) Ok, so we have been talking about theories that deal with the effects of human activity on the climate. But today I’d like to talka little bit about other theories that canexplain variations in climate. And one of the best-known is called the Milankovitch Hypothesis
Q:What is the lecture mainly about?
AA hypothesis that explains how changes in Earth’s motions affect climate.
BA hypothesis that explains why the shape of earth’s orbit varies over time.
CReasons it is difficult to find evidence to support hypotheses about the climate.
DAnalyses of the accuracy of data collected in different ways.
分析：
这是一道简单的主旨题。我们之前说过，新托福听力段子一般会在前几句出现主旨，所以考生一定要留意前几句的内容。录音文本中的划线部分为重点。只要抓住了variations in climate，就可以轻松选出A。在记笔记时，重点标出“climate 变”即可。
2)Now, when Milankovitch first proposed this theory in the 1920s, many of his colleagues were skeptical. Milankovitch didn’t have any proof. Actually there wouldn’t be any evidence to support his hypothesis until the 1970s, when oceanographers were able to drill deep into the seafloor and collect samples, samples which were then analyzed by geologists...and this showed that earth’s climate had changed pretty much the wayMilankovitch’s hypothesis suggested it would.So this evidence was pretty strong supportfor the Milankovitch Hypothesis.And by the 1980s, most people accepted this theory.
However, in the late 1980s, some scientists were exploring Devil’sHole…Well, the Devil’ s Hole findings contradictedthe ones obtained during the 1970s, so basically the question was, were the ages of one or both the samples were wrong, or were scientists misunderstanding the significance of the evidence.
Q:What is the significance of the evidence found on the ocean floor?
AIt negated earlier evidence that Milankovitch found.
BIt led the development of new methods to measure global climate changes.
CIt helped Milankovitch first formulate his hypothesis.
DIt confirmed Milankovitch’s hypothesis.
分析：
解这道题的关键在于ocean floor。原文中提到pretty strong support，所以应该是支持性的，选D。考生注意，只要出现不同理论，一定要搞清楚理论列出来的目的，即它所支持的内容是什么。
16. What did calcite deposits from Devil’s Hole reveal?
AInaccurate information about long-term climate changes.
BEvidence that contradicted Milankovitch’s hypothesis.
CEvidence that climate changes occur only locally.
DVariations in Earth’s orbit that had little impact on climate.
分析：
这道题故意绕了个弯子。我们前面提到，米兰科维奇假说在70年代被证实，在此前是没有证据的;下文又说80年代时在魔窟里发现的方解石样本又与70年代sea floor中发现的样本相冲突，因此可以得出结论：魔窟里的发现是不支持米兰科维奇假说的，所以选B。
背景知识：
米兰科维奇假说认为地球运动的变化，特别是绕太阳轨道的变化，这些变化会导致太阳到达地球能量的不同。并且正是这些从太阳到达地球能量的不同导致了地球气候的变化。
三、考点追踪
地球环境的听力段子难度不会太大，主要考察以下几点：
☆主旨靠前
考生一定要竖起耳朵仔细听前几句。
☆上下文逻辑关系
这不仅要看逻辑信号词，还得留心段与段之间的关系，体会一下是支持还是反对。如果有不同理论或研究调查的出现，要搞清每个支持什么观点。
☆表示判断的词
比如这里出现的support和contradict。
☆分类顺序词
理论中可能会涉及到许多因素，记笔记时要分条列点，注意条理性，这也能加快找答案的速度。
地球环境学的听力段子在新托福听力中屡见不鲜，官方指南中也有相关的题目，考生可以去练习。其实，熟悉话题对考生来说作用有两个：巩固场景词汇和心理适应。在做题的过程中积累词汇，同时适应这方面的内容，在考试中遇到就不会那么慌乱。