『新东方在线托福阅读』为托福考生准备了ETS托福TPO/Official 56 Passage 1阅读练习：What was the dilemma that Wegener solved?真题题目及答案解析，TPO/Official 56 Passage 1阅读原文范文音频翻译

托福TPO/Official 56 Passage 1阅读原文What was the dilemma that Wegener solved?题目答案及解析-新东方托福官方网校手机版

阿尔弗雷德·魏格纳的大陆漂移理论

Alfred Wegener's Theory of Continental Drift

1912年，德国地质学家阿尔弗雷德·魏格纳提出，地球上的大陆是由较轻的地壳组成的移动筏，随着时间的推移，它们穿过密度较大的海洋地壳。

In 1912, the German geologist Alfred Wegener proposed that Earth's continents are mobile rafts of lighter crust that have shifted over time by plowing their way through the denser crust of the oceans.

该理论被称为大陆漂移理论的部分原因是南美和非洲海岸线的明显吻合，就如拼图碎片一样。

The theory, called continental drift, was partly motivated by the apparent fit, like puzzle pieces, of the coastlines of South America and Africa.

韦格纳首先在一次会议上和一篇论文中提出了他的大陆漂移理论，而后在1915年出版了《大陆和海洋的起源》一书。

Wegener first presented his theory of continental drift at a meeting and in a paper, and then as a book, The Origin of Continents and Oceans, published in 1915.

他继续更新这部作品的版本，直到1930年在去格陵兰的探险中不幸去世。

He continued to write updated versions of this work until his death in an ill-fated expedition to Greenland in 1930.

韦格纳坚持认为，地球是由同心壳组成的，从地壳到地核，密度不断增加。

Wegener maintained that Earth is composed of concentric shells of increasing density from crust to core.

最外层的外壳不是连续的，而是由漂浮在海下较厚的sima(富硅和富镁岩石)中的较轻岩石的大陆块sial(富硅和富铝岩石的首字母缩写)组成。

The outermost shell is not continuous but made of continental blocks of lighter rock called sial (an acronym for silica-and aluminum-rich rock) floating in the denser sima (silica-and magnesia-rich rock) underlying the oceans.

所有的大陆构成了Pangaea超大陆。

All the continents had been joined in the supercontinent of Pangaea.

韦格纳认为，随着大陆的分裂，碎片的移动留下了一些碎片，这就解释了非火山岛和岛链的存在。

As the continent broke up, the pieces moving apart left bits behind, explaining the presence of nonvolcanic islands and island chains, according to Wegener.

移动的碎片碰撞的地方就形成了山脉。

Where the moving pieces collided, mountains formed.

它们要么是由于硅镁层向上推动形成，如安第斯山脉，要么是由于两块硅石的碰撞形成，如喜马拉雅山脉。

They were thrust up either by the plowing of the continents through the sima, as in the case of the Andes, or by the colliding of two blocks of sial, as in the case of the Himalayas.

关于驱动大陆漂移的力，韦格纳最初认为是Polfluchtkraft（一种由于地球自转而导致从两极像别处扩散的力），后来又认为是地球与月球和太阳之间引力产生的潮汐力。

As for the force driving continental drift, Wegener initially invoked Polfluchtkraft—a force causing flight from the poles as a result of Earth’s rotation—and later the tidal force resulting from the gravitational attraction between Earth and the Moon and Sun.

在大陆漂移学说大家庭中，最有影响力的地质学家之一是亚瑟·霍尔姆斯。

One of the most influential geologists to join the mobilist camp, as the drifters school became known, was Arthur Holmes.

霍尔姆斯认识到最近才发现的放射性热的重要性，并意识到一定有某种机制可以将它从地球内部消除。

Holmes recognized the importance of radioactive heat-which had recently been discovered-and realized that there must be a mechanism to remove it from Earth's interior.

他认为这种机制就是对流——即密度较小的物质上升，密度较大的物质下沉。

That mechanism, he argued, is convection-the rising of less dense material and the sinking of more dense material.

他紧接着提出地幔(在地球外壳与地核之间的内部部分)以大循环的方式对流，这种运动让各大洲在地球表面漂移。

He went on to propose that the mantle (the part of Earth's interior below the outer crust and above the core) convects in large, circulating patterns, and that this motion carries the continents across Earth's surface.

他还将地壳运动和地幔对流与山带的演化联系在一起。

He also related crustal movement and mantle convection to the evolution of mountain belts.

韦格纳在他的理论的最终诠释中采用了霍尔姆斯的机制。

Wegener adopted Holmes's mechanism in the last rendition of his theory.

霍尔姆斯在1944年出版了颇具影响力且广受欢迎的著作《自然地质学原理》，在该书中提出了他关于动态地球的宏大概念。

Holmes, for his part, presented his grand concept of a dynamic Earth in his influential and popular text Principles of Physical Geology, published in 1944.

尽管韦格纳的大陆漂移理论最终被板块构造理论所取代，但它对科学产生了影响，因为它解释了不同的观测结果，它被置于现有理论的背景中，同时也提供了对地球演化的连贯观点。

Although it was eventually supplanted by the theory of plate tectonics, Wegener's theory of continental drift influenced science because it explained disparate observations, because it was placed in the context of existing theories, and because it offered a coherent view of Earth's evolution.

例如，韦格纳不仅证明了大西洋两岸的海岸线是吻合的，而且不同大陆的地质特征也是吻合的。

For example, Wegener showed not only that the coastlines on opposite sides of the Atlantic fit together, but that geologic features on the different continents fit as well.

他断言，阿巴拉契亚山脉可以通过加拿大海事省向北延伸，与苏格兰和挪威的加里东山脉相匹配。

He asserted that the Appalachians, which can be traced northward through the Canadian Maritime Provinces, match the Caledonian Mountains in Scotland and Norway.

他收集了化石和生物物种分布的证据，认为与大陆相连的大陆桥不太可能是一个单一的大陆。

He marshaled evidence from the distributions of fossil and living species to argue that land bridges joining continents were less likely than a single continent.

经常被引用的例子是Mesosaurus，一种生活在二叠纪的海岸线食腐爬行动物，在南大西洋两岸的岩石中都发现它的化石。

The example commonly cited is that of Mesosaurus, a shoreline scavenger reptile that lived in the Permian period and is found as fossils in rocks on both sides of the South Atlantic Ocean.

人们认为Mesosaurus不擅长游泳，当然也就不能横渡海洋。

Mesosaurus was thought not to be a great swimmer, certainly not able to cross an ocean.

韦格纳还在古代气候中发现了支撑证据。

Wegener also found supporting evidence in ancient climates.

越来越多的观测表明，许多地区过去的气候与现在的气候有很大差异。

Mounting observations indicated that the past climate of many regions was much different from the present climate.

在热带地区，地质学家发现了古代冰川留下的沙子和砾石，而在多雨地区，他们发现了史前沙漠。

In the tropics, geologists had found sand and gravel left by ancient glaciers, and in rainy regions they had located prehistoric deserts.

然后，一个英国探险队在距南极仅600公里(370英里)的地方发现了植物化石。

Then there was the discovery, by a British expedition, of plant fossils only 600 kilometers (370 miles) from the South Pole.

特别令人困惑的是，有证据表明，同一时间不同地区的气候相差甚远，所以不能简单地说，整个地球曾经比现在更热，或曾经比现在更冷来解释不同的气候。

Particularly puzzling was evidence suggesting that widely different climates in different regions had occurred at the same time, so one could not account for different climates by claiming simply that the whole of Earth was once hotter or once cooler than now.

韦格纳解决了这个难题，他指出，如果大陆的位置相对于两极的位置发生了移动，那么古气候的观测结果就可以得到解释。

Wegener solved this dilemma by showing that observations of paleoclimate could be explained if the positions of the continents had shifted relative to those of the poles.

According to paragraph 1, the presence of nonvolcanic islands was an indication to Wegener that

Why are the Andes and Himalaya mountains mentioned in the discussion in paragraph 1?

Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

What does paragraph 2 suggest about how Holmes influenced Wegener's thinking?

What is the importance of Wegener's observation that "the Appalachians, which can be traced northward through the Canadian Maritime Provinces, match the Caledonian Mountains in Scotland and Norway"?

The word "asserted" in the passage is closest in meaning to

Mesosaurus is mentioned in paragraph 3 to make which of the following points?

What was the dilemma that Wegener solved?

Look at the four squares  that indicate where the following sentence could be added to the passage. The publication was met by skepticism from scientists the world over, yet he refused to become discouraged.  Where would the sentence best fit? Click on a square  to add the sentence to the passage.

Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

Alfred Wegener’s Theory of Continental Drift In 1912, the German geologist Alfred Wegener proposed that Earth’s continents are mobile rafts of lighter crust that have shifted over time by plowing their way through the denser crust of the oceans.The theory, called continental drift, was partly motivated by the apparent fit, like puzzle pieces, of the coastlines of South America and Africa. Wegener first presented his theory of continental drift at a meeting and in a paper, and then as a book, The Origin of Continents and Oceans, published in 1915.He continued to write updated versions of this work until his death in an ill-fated expedition to Greenland in 1930. Wegener maintained that Earth is composed of concentric shells of increasing density from crust to core. The outermost shell is not continuous but made of continental blocks of lighter rock called sial (an acronym for silica- and aluminum-rich rock) floating in the denser sima (silica- and magnesia-rich rock) underlying the oceans. All the continents had been joined in the supercontinent of Pangaea. As the continent broke up, the pieces moving apart left bits behind, explaining the presence of nonvolcanic islands and island chains, according to Wegener. Where the moving pieces collided, mountains formed. They were thrust up either by the plowing of the continents through the sima, as in the case of the Andes, or by the colliding of two blocks of sial, as in the case of the Himalayas. As for the force driving continental drift, Wegener initially invoked Polfluchtkraft—a force causing flight from the poles as a result of Earth’s rotation—and later the tidal force resulting from the gravitational attraction between Earth and the Moon and Sun. One of the most influential geologists to join the mobilist camp, as the drifters school became known, was Arthur Holmes. Holmes recognized the importance of radioactive heat—which had recently been discovered—and realized that there must be a mechanism to remove it from Earth’s interior. That mechanism, he argued, is convection—the rising of less dense material and the sinking of more dense material. He went on to propose that the mantle (the part of Earth’s interior below the outer crust and above the core) convects in large, circulating patterns, and that this motion carries the continents across Earth’s surface. He also related crustal movement and mantle convection to the evolution of mountain belts. Wegener adopted Holmes’s mechanism in the last rendition of his theory. Holmes, for his part, presented his grand concept of a dynamic Earth in his influential and popular text Principles of Physical Geology, published in 1944. Although it was eventually supplanted by the theory of plate tectonics, Wegener’s theory of continental drift influenced science because it explained disparate observations, because it was placed in the context of existing theories, and because it offered a coherent view of Earth’s evolution. For example, Wegener showed not only that the coastlines on opposite sides of the Atlantic fit together, but that geologic features on the different continents fit as well. He asserted that the Appalachians, which can be traced northward through the Canadian Maritime Provinces, match the Caledonian Mountains in Scotland and Norway. He marshaled evidence from the distributions of fossil and living species to argue that land bridges joining continents were less likely than a single continent. The example commonly cited is that of Mesosaurus, a shoreline scavenger reptile that lived in the Permian period and is found as fossils in rocks on both sides of the South Atlantic Ocean. Mesosaurus was thought not to be a great swimmer, certainly not able to cross an ocean. Wegener also found supporting evidence in ancient climates. Mounting observations indicated that the past climate of many regions was much different from the present climate. In the tropics, geologists had found sand and gravel left by ancient glaciers, and in rainy regions they had located prehistoric deserts. Then there was the discovery, by a British expedition, of plant fossils only 600 kilometers (370 miles) from the South Pole. Particularly puzzling was evidence suggesting that widely different climates in different regions had occurred at the same time, so one could not account for different climates by claiming simply that the whole of Earth was once hotter or once cooler than now. Wegener solved this dilemma by showing that observations of paleoclimate could be explained if the positions of the continents had shifted relative to those of the poles.