在之前的文章中，有為考生們講解過地理地質學的內容，在本篇，我們進一步來研究一下地球環境學科。前者往往和化學以及考古學有所交叉，后者的內容更接近我們的實際生活或認知，比如環境變化。當然也會涉及到許多場景詞匯，廣大考生在備考過程中還是要認真復習備考。今天帶領大家具體看一下地球環境學類的聽力段子應該如何應對。
一、概述
這一學科要求考生們要關注一些時事，并且擴大自己知識面，開拓視野，可以和地理地質學科一起關注。
☆大氣環境，例如赤道無風帶，大氣環流，全球氣候變化。
☆地面環境，例如風能，地下水的研究與保護。
☆海洋環境，例如海底熱液，潮汐能。
☆其他話題，可能和天文學，生物學，地理地質學等產生交叉。
在此，考生最好能積累背景知識，多瀏覽一些原汁原味的報刊雜志，比如Scientific Americans、National Geographical等等，多積累相關詞匯，熟悉發音。當然，剛才也提到了，新托福聽力段子所涉及的話題往往千變萬化且有所交叉，考生在熟悉背景知識的同時也要打牢基礎，培養快速辨音能力和短時記憶能力，才能以不變應萬變。
二、案例分析
請看一個地球環境學的經典案例：
E.G.TPO17 Milankovitch Hypothesis
聽力原文：
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：
這是一道簡單的主旨題。我們之前說過，新托福聽力段子一般會在前幾句出現主旨，所以考生一定要留意前幾句的內容。錄音文本中的劃線部分為重點。只要抓住了variations in climate，就可以輕松選出A。在記筆記時，重點標出“climate 變”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：
解這道題的關鍵在于ocean floor。原文中提到pretty strong support，所以應該是支持性的，選D。考生注意，只要出現不同理論，一定要搞清楚理論列出來的目的，即它所支持的內容是什么。
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：
這道題故意繞了個彎子。我們前面提到，米蘭科維奇假說在70年代被證實，在此前是沒有證據的;下文又說80年代時在魔窟里發現的方解石樣本又與70年代sea floor中發現的樣本相沖突，因此可以得出結論：魔窟里的發現是不支持米蘭科維奇假說的，所以選B。
背景知識：
米蘭科維奇假說認為地球運動的變化，特別是繞太陽軌道的變化，這些變化會導致太陽到達地球能量的不同。并且正是這些從太陽到達地球能量的不同導致了地球氣候的變化。
三、考點追蹤
地球環境的聽力段子難度不會太大，主要考察以下幾點：
☆主旨靠前
考生一定要豎起耳朵仔細聽前幾句。
☆上下文邏輯關系
這不僅要看邏輯信號詞，還得留心段與段之間的關系，體會一下是支持還是反對。如果有不同理論或研究調查的出現，要搞清每個支持什么觀點。
☆表示判斷的詞
比如這里出現的support和contradict。
☆分類順序詞
理論中可能會涉及到許多因素，記筆記時要分條列點，注意條理性，這也能加快找答案的速度。
地球環境學的聽力段子在新托福聽力中屢見不鮮，官方指南中也有相關的題目，考生可以去練習。其實，熟悉話題對考生來說作用有兩個：鞏固場景詞匯和心理適應。在做題的過程中積累詞匯，同時適應這方面的內容，在考試中遇到就不會那么慌亂。