Scattered around the globe are more than 100 small regions of isolated volcanic activity known to geologists as hot spots. Unlike most of the world's volcanoes, they are not always found at the boundaries of the great drifting plates that make up the earth's surface; on the contrary, many of them lie deep in the interior of a plate. Most of the hot spots move only slowly, and in some cases the movement of the plates past them has left trails of dead volcanoes. The hot spots and their volcanic trails are milestones that mark the passage of the plates.

That the plates are moving is not beyond dispute. Africa and South America, for example, are moving away from each other as new material is injected into the sea floor between them. The complementary coastlines and certain geological features that seem to span the ocean are reminders of where the two continents were once joined. The relative motion of the plates carrying these continents has been constructed in detail, but the motion of one plate with respect to another cannot readily be translated into motion with respect to the earth's interior. It is not possible to determine whether both continents are moving in opposite directions or whether one continent is stationary and the other is drifting away from it. Hot spots, anchored in the deeper layers of the earth, provide the measuring instruments needed to resolve the question. From an analysis of the hot spot population it appears that the African plate is stationary and that it has not moved during the past 30 million years.

The significance of hot spots is not confined to their role as a frame of reference. It now appears that they also have an important influence on the geophysical processes that propel the plates across the globe. When a continental plate come to rest over a hot spot, the material rising from deeper layer creates a broad dome. As the dome grows, it develops seed fissures (cracks); in at least a few cases the continent may break entirely along some of these fissures, so that the hot spot initiates the formation of a new ocean. Thus just as earlier theories have explained the mobility of the continents, so hot spots may explain their mutability (inconstancy).

67. The author believes that _____.
[A] the motion of the plates corresponds to that of the earth's interior
[B] the geological theory about drifting plates has been proved to be true
[C] the hot spots and the plates move slowly in opposite directions
[D] the movement of hot spots proves the continents are moving apart

[答案] B

[解題思路]

本題也需要與文章具體內容進行一一對應以便排除錯誤選項。首先，第二段第四句話談到"The relative motion of the plates carrying these continents has been constructed in detail, but the motion of one plate with respect to another cannot readily be translated into motion with respect to the earth's interior"（帶著兩個大陸板塊漂移的相對運動已經能夠被詳細地闡述出來，但一個板塊相對另一板塊的運動還不能輕易地解釋為它們相對于地球內部的運動），因此A選項顯然與原文表述是矛盾的。接下來第五句話進一步說"It is not possible to determine whether both continents are moving in opposite directions or whether one continent is stationary and the other is drifting away from it"（人們還不能確定兩個大陸是在朝相反的方向運動，也不能確定是否一個大陸停止不動而另一個離它而去），因此C、D選項也與原文不符合。而第二段第一句話明確指出"That the plates are moving is not beyond dispute"（板塊漂移這一理論現在是無可爭辯的了），可見B選項符合正確答案。

[題目譯文]

作者相信              。
[A] 板塊的移動與地球內部的移動是一致的
[B] 關于板塊漂移的地質理論已經被證明是正確的
[C] 熱區和板塊朝著相反的方向緩慢移動
[D] 熱區的移動證明了大陸正在彼此分開

68. That Africa and South America were once joined can be deduced from the fact that _____ .
[A] the two continents are still moving in opposite directions
[B] they have been found to share certain geological features
[C] the African plates has been stable for 30 million years
[D] over 100 hot spots are scattered all around the globe

[答案] B

[解題思路]

Africa 和South America的例子對應于文章第二段的第二、三句話"Africa and South America, for example, are moving away from each other as new material is injected into the sea floor between them. The complementary coastlines and certain geological features that seem to span the ocean are reminders of where the two continents were once joined"（以非洲和南美洲為例，由于有新的物質嵌入二者之間的海底，兩個大洲之間的距離越來越遠。但互相吻合的海岸線和某些似乎跨越海洋的地質特征會使人想到這兩個大陸曾經是連成一片的），因此很容易定位正確答案為B。

[題目譯文]

能夠證明非洲和南美洲曾經相連的事實是                。
[A] 這兩塊大陸仍然在朝相反的方向漂移
[B] 人們發現它們有某些相同的地質特征
[C] 非洲板塊已經穩定了3000萬年
[D] 全球散布著100多個熱區

69. The hot spot theory may prove useful in explaining _____ .
[A] the structure of the African plates
[B] the revival of dead volcanoes
[C] the mobility of the continents
[D] the formation of new oceans

[答案] D

[解題思路]

本文可以采用排除法。首先，A選項在文章中沒有提及，B選項的"dead vocalnoes"也是在文章第一段最后順帶提及，并不是用熱區理論要解釋的現象。文章最后一句話提到"as earlier theories have explained the mobility of the continents"（正像早期的理論解釋了大陸的可移動性一樣），說明大陸移動性不需要用熱區理論來解釋，而是用早期理論解釋，因此C選項錯誤。D選項對應于文章最后一段倒數第二句話"As the dome grows, it develops seed fissures (cracks); in at least a few cases the continent may break entirely along some of these fissures, so that the hot spot initiates the formation of a new ocean"（至少有幾次，大陸可能會沿著其中的一些裂縫完全裂開了，因此這個熱區就引發了一個新海洋的形成），因而D是正確答案。

[題目譯文]

熱區理論可能有力地解釋          。
[A] 非洲板塊的結構
[B] 死火山的復活
[C] 大陸的移動性
[D] 新大洋的形成

　　相關推薦：考研英語閱讀理解命題思路透析和真題揭秘(31)

　　　　　　　2009考研英語考前狂背作文：應用文范文匯總