GRE閱讀｜Because of its accuracy in outlining the Earth's subsurface, the seismic-reflection method remains the most important tool－熱血背包客莊ㄟ

Because of its accuracy in outlining the Earth's subsurface, the seismic-reflection method remains the most important tool in the search for petroleum reserves. In field practice, a subsurface is mapped by line arranging a series of wave-train sources, such as small dynamite explosions, in a grid pattern. As each source is activated, it generates a wave train that moves downward at a speed determined uniquely by the rock's elastic characteristics. As rock interfaces are crossed, the elastic characteristics encountered generally change abruptly, which causes part of the energy to be reflected back to the surface, where it is recorded by seismic instruments. The seismic records must be processed to correct for positional differences between the source and the receiver, for unrelated wave trains, and for multiple reflections from the rock interfaces. Then the data acquired at each of the specific source locations are combined to generate a physical profile of the subsurface, which can eventually be used to select targets for drilling.

For the following question, consider each of the choices separately and select all that apply

1. According to the passage, in the seismic-reflection method which of the following have a significant effect on the signal detected by the seismic instruments

(A) presence of unrelated wave trains

(B) placement of the seismic instruments

2. It can be inferred from the passage that the seismic-reflection method would be likely to yield an inaccurate physical profile of the subsurface in which of the following circumstances?

(A) If the speed at which the wave train moved downward changed

(B) If the receiver were not positioned directly at the wave-train source

(C) If the rock on one side of a rock interface had similar elastic characteristics to those of the rock on the other side

(D) If the seismic records obtained for the different sources in a grid were highly similar to each other

(E) If there were no petroleum deposits beneath the area defined by the grid of wave-train sources

3. Which of the following best describes the organization of the passage?

(A) A method is criticized, and an alternative is suggested.

(B) An illustration is examined, and some errors are exposed.

(D) A series of examples is presented, and a conclusion is drawn.

(E) A hypothesis is advanced, and supporting evidence is supplied.

結構分析：

這文章基本上看完第一句話主幹就出來了，因為我沒喵到轉折，所以是一個大順子文章，再來從In field practice這三個字開始往後都是介紹他的製程方式，這文章根本就是ＳＯＰ，投資基金有賺有賠，投資基金有風險，申購請詳閱公開說明書，的那份說明書，我怎麼知道，因為論文上的主幹都是作者想表達的抽象思想概念，但是In field practice是一個動作的實踐，他是具體東西，表示已經在為主幹提供舉例了，然後In field practice之後句子跟句子之間環環相扣，直接用上一句話的某內容，直接往下一句話貼上，一步一步的延伸，所以把只要把它封裝成一個practice即可。總結：開頭給一個概念，然後我給一個例子practice，因此本文只要將第一句熟讀之後主幹就到位了，practice!!! you're talking about practice, not a game!!!!

Because of its accuracy in outlining the Earth's subsurface, the seismic-reflection method remains the most important tool in the search for petroleum reserves.

ＳＭ是用來找油的好方法，因為its accuracy夠精確。

For the following question, consider each of the choices separately and select all that apply

1. According to the passage, in the seismic-reflection method which of the following have a significant effect on the signal detected by the seismic instruments

(A) presence of unrelated wave trains

(B) placement of the seismic instruments

解題：　　

關鍵字the signal detected by the seismic instruments定位到：

As rock interfaces are crossed, the elastic characteristics encountered generally change abruptly, which causes part of the energy to be reflected back to the surface, where it is recorded by seismic instruments.The seismic records must be processed to correct for positional differences between the source and the receiver, for unrelated wave trains, and for multiple reflections from the rock interfaces.

訊號就是紀錄，所以找到這兩句話，而第一句的尾巴seismic records是the surface的關係副詞裡面的內容，然後the surface又是關係代名詞的內容，因此都是修飾，沒實質意義，第一句的重點是elastic characteristics change，還有前方的副詞子句，因為這個characteristics＝（Ｃ）properties，再來rock interfaces are crossed＝（Ｃ）through which...traveled，好了一個被選起來了，往下一句話出發，發現了關鍵unrelated wave trains＝（Ａ），positional differences＝（Ｂ），source and the receiver是instruments的零件。照理說『考點應該是for...的的並列結構』，可是我實在很難聯想到multiple reflections from the rock ＝properties of rocks，各式各樣的反射就是一種特徵嗎？？那為麼要加Ｓ，沒差！！who care....『SSSSSS』要加『Ｓ』，答案還是被我選到了，選（Ａ）（Ｂ）（Ｃ）

2. It can be inferred from the passage that the seismic-reflection method would be likely to yield an inaccurate physical profile of the subsurface in which of the following circumstances?

(A) If the speed at which the wave train moved downward changed

(B) If the receiver were not positioned directly at the wave-train source

(C) If the rock on one side of a rock interface had similar elastic characteristics to those of the rock on the other side

(D) If the seismic records obtained for the different sources in a grid were highly similar to each other

(E) If there were no petroleum deposits beneath the area defined by the grid of wave-train sources

解題：

找到對比對象，題目是an inaccurate所以文章應該就是要找

The seismic records must be processed to correct for positional differences between the source and the receiver, for unrelated wave trains, and for multiple reflections from the rock interfaces.

inaccurate VS. correct，一個正確一個不正確，他們邏輯上一定相反，那就看文章內容說如果正確的話會如何，之後再取反就是答案了，我們從文章中找到positional differences，因此取反要找個是 not differences選（Ｃ）

補充：

可是（Ｄ）也有個similar為啥不選，因為主詞錯了，今天的對比對象是『正確』的地震紀錄VS.『不正確』的地震紀錄，兩者是以地震紀錄當座標系原點，因此不是拿seismic records去比。

3. Which of the following best describes the organization of the passage?

(A) A method is criticized, and an alternative is suggested.

(B) An illustration is examined, and some errors are exposed.

(D) A series of examples is presented, and a conclusion is drawn.

(E) A hypothesis is advanced, and supporting evidence is supplied.

解題：

大順子結構，一個概念加上一個舉例，然後這個舉例是一組製程，所以（Ａ）alternative就不對了，（Ｂ）errors沒有轉折，舉例一定順向，（Ｃ）跟（Ｄ）差異就是（Ｄ）少了一個開頭主題句，（Ｅ）hypothesis他沒有主觀推，敲，猜，這文章是事實是客觀。選（Ｃ）

以上筆記供大夥參考若有錯誤再煩請指教