GMAT閱讀輔導(dǎo) 超詳細(xì)答案解析

According to a recent theory(注意，提出最新理論，后一般展開(kāi)理論具體內(nèi)容), Archean-age gold-quartz vein systems were formed more than two billion years ago from magmatic fluids that originated from molten granite-like bodies deep beneath the surface of the Earth. //(第一層：介紹最新的關(guān)于太古代年齡黃金石英脈系統(tǒng)的形成理論)This theory is contrary to (與...相反)the widely held view (注意，提出被廣泛認(rèn)可的理論，后一般展開(kāi)理論具體內(nèi)容)that the systems were deposited from metamorphic fluids, that is, from fluids that formed during the dehydration of wet sedimentary tocks.(此句修飾metamorphic fluids，第一遍讀文時(shí)可略讀)//(第二層：介紹與最新理論相悖的被廣泛認(rèn)可的理論)

The recently developed theory has considerable practical importance(正評(píng)價(jià)詞). Most of the gold deposits discovered during the original gold rushes were exposed at the Earth’s surface and were found because they had shed trails of alluvial gold that were easily traced by simple prospecting methods. Although(結(jié)構(gòu)詞，表讓步)these same methods still lead to an occasional discovery, most deposits not yet discovered have gone undetected because they are buried and have no surface expression.//(第一層：最新理論的重大實(shí)踐意義：最初發(fā)現(xiàn)金礦只需簡(jiǎn)單地根據(jù)砂金痕跡探測(cè)，而現(xiàn)在由于大多數(shù)金礦埋于地下，不易被發(fā)現(xiàn))

The challenge in exploration is therefore(結(jié)構(gòu)詞，表因果聯(lián)系) to unravel the subsurface geology of an area and pinpoint the position of buried minerals. Methods widely used today include(后提出三種現(xiàn)今使用的方法) (①analysis of aerial images that yield a broad geological overview;) ( ②geophysical techniques that provide data on the magnetic, electrical, and mineralogical properties of the rocks being investigated;) and (③sensitive chemical tests that are able to detect the subtle chemical halos that often envelop mineralization.)//(第一層：金礦勘測(cè)的難點(diǎn)以及目前廣泛使用的三種探測(cè)方法)However( 結(jié)構(gòu)詞，表轉(zhuǎn)折關(guān)系), none of these high-technology methods are of any value(負(fù)評(píng)價(jià)詞)if the sites to which they are applied have never mineralized, and to maximize the chances of discovery the explorer must therefore(結(jié)構(gòu)詞，表因果) pay particular attention to selecting the ground formations most likely to be mineralized. //(第二層：如果勘察的地點(diǎn)從來(lái)沒(méi)有礦化，那么目前被廣泛使用的高科技方法就沒(méi)有一個(gè)有價(jià)值)Such ground selection (指代selecting the ground formations most likely to be mineralized)relies to varying degrees on conceptual models, which take into account theoretical studies of relevant factors.//(第三層：地層選擇依賴于概念模型的程度變化，而概念模型要考慮相關(guān)因素的理論研究)

These models(指代conceptual models) are constructed primarily from empirical observations of known mineral deposits and from theories of ore-forming processes. The explorer uses the models to identify(概念模型作用之一) those geological features that are critical to the formation of the mineralization being modeled, and then tries to select areas (概念模型作用之二)for exploration that exhibit as many of the critical features as possible.//(第一層：概念模型的建立依據(jù)和作用)

邏輯簡(jiǎn)圖：觀點(diǎn)對(duì)比型

第一段

第一層：介紹最新的關(guān)于太古代年齡黃金石英脈系統(tǒng)形成理論。

第二層：介紹與最新理論相悖的被廣泛認(rèn)可的理論。

第二段

第一層：最新理論的重大實(shí)踐意義：最初發(fā)現(xiàn)金礦只需簡(jiǎn)單地根據(jù)砂金痕跡探測(cè)，而現(xiàn)在由于大多數(shù)金礦埋于地下，不易被發(fā)現(xiàn)。

第三段

第一層：金礦勘測(cè)的難點(diǎn)以及目前廣泛使用的三種探測(cè)方法。

第二層：如果勘察的地點(diǎn)從來(lái)沒(méi)有礦化，那么目前被廣泛使用的高科技方法就沒(méi)有一個(gè)有價(jià)值。

第三層：地層選擇依賴于概念模型的程度變化，而概念模型要考慮相關(guān)因素的理論研究。

第四段

第一層：概念模型的建立依據(jù)和作用。

1.The author is primarily concerned with(主旨題)

A.advocating a return to an older methodology(提倡回歸傳統(tǒng)方法，不符合原文內(nèi)容，排除)

B.explaining the importance of a recent theory(解釋最近的一種理論的重要性，符合文章內(nèi)容，正確)

C.enumerating differences between two widely used methods(列舉二種被廣泛運(yùn)用的理論的差異，不符合原文內(nèi)容，排除)

D.describing events leading to a discovery(描述事件導(dǎo)致的發(fā)現(xiàn)，不符合原文內(nèi)容，排除)

E.challenging the assumptions on which a theory is based(質(zhì)疑建立理論的假設(shè)，不符合原文內(nèi)容，排除)

2.According to the passage, the widely held view of Archean-age gold-quartz vein systems is that such systems(細(xì)節(jié)題)回文定位至第一段第二層

A.were formed from metamorphic fluids( 正確，對(duì)應(yīng)文中This theory is contrary to the widely held view that the systems were deposited from metamorphic fluids)

B.originated in molten granite-like bodies(層次定位錯(cuò)誤， molten granite-like bodies是recent theory中提到的，排除)

C.were formed from alluvial deposits(段落定位錯(cuò)誤，alluvial deposits是在最初淘金方法中提到的，排除)

D.generally have surface expression(根據(jù)文章，是指 gold deposits exposed at the Earth’s surface，而非gold-quartz vein systems，排除)

E.are not discoverable through chemical tests(根據(jù)文章，chemical tests 能夠探測(cè)出礦化的金礦，所以應(yīng)是discoverable，排除)

3.The passage implies that which of the following steps would be the first performed by explorers who wish to maximize their chances of discovering gold?(推論題)

A.Surveying several sites known to have been formed more than two billion years ago(文中沒(méi)有任何信息表明超過(guò)20億年的site更有可能發(fā)現(xiàn)金礦，排除)

B.Limiting exploration to sites known to have been formed from metamorphic fluid(文章雖肯定了recent theory的實(shí)踐意義，但并不意味著要限制探索已知的由metamorphic fluid形成的sites，過(guò)分推理，排除)

C.Using an appropriate conceptual model to select a site for further exploration(正確， conceptual models可幫助研究人員找到最有可能礦化的site)

D.Using geophysical methods to analyze rocks over a broad area(根據(jù)文章，geophysical methods將沒(méi)有任何價(jià)值如果勘察的地點(diǎn)從來(lái)沒(méi)有礦化，排除)

E.Limiting exploration to sites where alluvial gold has previously been found(根據(jù)文章第二段，Although these same methods still lead to an occasional discovery, most deposits not yet discovered have gone undetected because they are buried and have no surface expression，排除)

4.Which of the following statements about discoveries of gold deposits is supported by information in the passage?(細(xì)節(jié)題)

A.The number of gold discoveries made annually has increased between the time of the original gold rushes and the present.(文章未涉及黃金發(fā)現(xiàn)的數(shù)量，排除)

B.New discoveries of gold deposits are likely to be the result of exploration techniques designed to locate buried mineralization.(正確，由于大多數(shù)金礦埋于地下，探測(cè)人員必須找到最有可能含有地下礦石的site)

C.It is unlikely that newly discovered gold deposits will ever yield as much as did those deposits discovered during the original gold rushes.(文章未涉及黃金發(fā)現(xiàn)的產(chǎn)量，排除)

D.Modern explorers are divided on the question of the utility of simple prospecting methods as a source of new discoveries of gold deposits.(根據(jù)文章，Although these same methods still lead to an occasional discovery, most deposits not yet discovered have gone undetected because they are buried and have no surface expression，現(xiàn)今的探測(cè)人員并沒(méi)有質(zhì)疑傳統(tǒng)方法的效用，排除)

E.Models based on the theory that gold originated from magmatic fluids have already led to new discoveries of gold deposits.(文章并沒(méi)說(shuō)在此model指導(dǎo)下找到金礦，排除)

5.It can be inferred from the passage that which of the following is easiest to detect?(推論題)

A.A gold-quartz vein system originating in magmatic fluids(根據(jù)文章，這是recent theory的觀點(diǎn)，但并沒(méi)說(shuō)此gold-quartz vein system 有易于探測(cè)的地表顯示，排除)

B.A gold-quartz vein system originating in metamorphic fluids(根據(jù)文章，這是被廣泛認(rèn)可的觀點(diǎn)，但并沒(méi)說(shuō)此gold-quartz vein system 有易于探測(cè)的地表顯示，排除)

C.A gold deposit that is mixed with granite(文章并未涉及gold deposit that is mixed with granite，排除)

D.A gold deposit that has shed alluvial gold(正確，對(duì)應(yīng)文中g(shù)old deposits were found because they had shed trails of alluvial gold that were easily easily traced by simple prospecting methods)

E.A gold deposit that exhibits chemical halos(文中第三段第一層提到了關(guān)于chemical halos的test，但顯然這不是 the easiest means)

6.The theory mentioned in line1-5 relates to the conceptual models discussed in the passage in which of the following ways?(細(xì)節(jié)題)回文定位至第一段第一層

A.It may furnish a valid account of ore-forming processes, and, hence, can support conceptual models that have great practical significance.(符合原文內(nèi)容，正確)

B.It suggests that certain geological formations, long believed to be mineralized, are in fact mineralized, thus confirming current conceptual models.(最新理論未確認(rèn)models，不符合原文內(nèi)容，排除)

C.It suggests that there may not be enough similarity across Archean-age gold-quartz vein systems to warrant the formulation of conceptual models.(與原文內(nèi)容相反，根據(jù)文章，最近理論有利于 the formulation of conceptual models，排除)

D.It corrects existing theories about the chemical halos of gold deposits, and thus provides a basis for correcting current conceptual models.(不符合原文內(nèi)容，根據(jù)文章，最新理論并未correct existing theories about the chemical halos，相反最新理論還有利于conceptual models的形成和發(fā)展，排除)

E.It suggests that simple prospecting methods still have a higher success rate in the discovery of gold deposits than do more modern methods.(最新理論未比較發(fā)現(xiàn)金礦的方法，無(wú)關(guān)方法的比較，排除)

7.According to the passage, methods of exploring for gold that are widely used today are based on which of the following facts?(細(xì)節(jié)題)

A.Most of the Earth’s remaining gold deposits are still molten.(文章未涉及molten gold，也未涉及探測(cè)molten gold的方法，排除)

B.Most of the Earth’s remaining gold deposits are exposed at the surface.(根據(jù)文章， most gold deposits are buried，排除)

C.Most of the Earth’s remaining gold deposits are buried and have no surface expression.(符合原文內(nèi)容，正確)

D.Only one type of gold deposit warrants exploration, since the other types of gold deposits are found in regions difficult to reach.(文章未涉及 types of gold deposits 和 難以探測(cè)到的regions，排除)

E.Only one type of gold deposit warrants exploration, since the other types of gold deposits are unlikely to yield concentrated quantities of gold.(文章未涉及types and yields of gold deposits，排除)