『新东方在线托福阅读』为托福考生准备了ETS托福TPO/Official 49 Passage 1阅读练习：According to paragraph 3, why is the height of a raised beach not a straightforward indicator of past sea level?真题题目及答案解析，TPO/Official 49 Passage 1阅读原文范文音频翻译

托福TPO/Official 49 Passage 1阅读原文According to paragraph 3, why is the height of a raised beach not a straightforward indicator of past sea level?题目答案及解析-新东方托福官方网校手机版

关于过去气候的资料主要与考古学有关，因为考古学能告诉我们过去气候对陆地以及人们生存所需的各种资源的影响。

Information on past climates is primarily of relevance to archaeology because of what it tells us about the effects on the land and on the resources that people needed to survive.

气候最重要的影响是在各个时期可用陆地的绝对数量上，陆地的绝对数量可以通过研究古海岸线来测量。

The most crucial effect of climate was on the sheer quantity of land available in each period, measurable by studying ancient coastlines.

在漫长的时间里，古海岸线在不断地变化，即使在相对近的时期也是如此，这从位于法国布列塔尼厄兰尼克岛的新石器时代巨石圆阵中就可以看出（该圆阵一度位于内陆，如今却在岛屿上，并且一半被淹没在水下）。位于英国约克郡东部的中世纪村庄也显示出古海岸线变化的证据，在过去的几百年内，随着北海向西扩张、侵蚀悬崖，这些村庄迅速地塌入了海中。

These have changed constantly through time, even in relatively recent periods, as can be seen from the Neolithic stone circle of Er Lannic, in Brittany, France (once inland but now half submerged on an island) or medieval villages in east Yorkshire, England, that have tumbled into the sea in the last few centuries as the North Sea gnaws its way westward and erodes the cliffs.

与之相反的是，河边沉积的淤泥有时会把海洋“推”回到更远的地方，创造出新的陆地。比如，在土耳其西部的以弗所，古罗马时代海岸上的一个港口如今却在内陆（距离海岸）约五公里的位置。

Conversely, silts deposited by rivers sometimes push the sea farther back, creating new land, as at Ephesus in western Turkey, a port on the coast in Roman times but today some five kilometers inland.

然而，对于关心旧石器时代漫长时期的考古学家而言，还有重要得多的海岸线变化要去考虑。

Nevertheless, for archaeologists concerned with the long periods of time of the Paleolithic period there are variations in coastlines of much greater magnitude to consider.

在世界范围内，大陆冰川的扩张与收缩引起了海平面巨幅且不均匀的升降。

The expansion and contraction of the continental glaciers caused huge and uneven rises and falls in sea levels worldwide.

当冰原增多，海平面就会下降，因为水被“锁”进了冰川里；当冰川融化，海平面就会再度上升。

When the ice sheets grew, the sea level would drop as water became locked up in the glaciers; when the ice melted, the sea level would rise again.

海平面的下降常常会暴露许多重要的陆桥，比如连接阿拉斯加和亚洲东北部的陆桥，以及连接不列颠和欧洲西北部的陆桥。这一现象不仅对人类全球殖民化影响深远，它对整体自然环境也有着深远的影响——隔离或孤立地区的动植物群会受到根本的，并且通常是不可逆转的影响。

Falls in sea level often exposed a number of important land bridges, such as those linking Alaska to northeast Asia and Britain to northwest Europe, a phenomenon with far-reaching effects not only on human colonization of the globe but also on the environment as a whole—the flora and fauna of isolated or insular areas were radically and often irreversibly affected.

如今的阿拉斯加和亚洲之间有一个白令海峡。这个海峡非常浅，海平面只要下降四米就能把它变成一座陆桥。

Between Alaska and Asia today lies the Bering Strait, which is so shallow that a fall in sea level of only four meters would turn it into a land bridge.

在约18000年前的盛冰期，当冰原覆盖最广泛的时候，研究者认为，海平面下降了约120米。这一下降因此创造的不仅是一座陆桥，而是一片广阔的平原。这片平原南北相距1000公里，被称为白令陆桥。

When the ice sheets were at their greatest extent some 18,000 years ago (the glacial maximum), it is thought that the fall was about 120 meters, which therefore created not merely a bridge but a vast plain, 1,000 kilometers from the north to the south, which has been called Beringia.

在关于人类殖民新大陆的可能路线和日期的持续争论中，白令陆桥的存在（以及它对人类生活的供养程度）是重要的证据之一。

The existence of Beringia (and the extent to which it could have supported human life) is one of the crucial pieces of evidence in the continuing debate about the likely route and date of human colonization of the New World.

评估过去的海平面升降需要研究近海岸被淹没的地表以及陆地上的上升海滩。

The assessment of past rises and falls in sea level requires study of submerged land surfaces off the coast and of raised or elevated beaches on land.

上升海滩是前海岸线的剩余部分，与现有海岸线相比，它处于较高位置，并且十分明显。比如，旧金山北部的加州海岸沿岸就有上升海滩。

Raised beaches are remnants of former coastlines at higher levels relative to the present shoreline and visible, for instance, along the Californian coast north of San Francisco.

然而，上升海滩相对于现有海岸线的高度，通常来讲并不能简单说明从前海平面的高度。

The height of a raised beach above the present shoreline, however, does not generally give a straightforward indication of the height of a former sea level.

在大多数情况下，上升海滩处于较高位置，是因为陆地被均衡上升或构造运动抬起来了。

In the majority of cases, the beaches lie at a higher level because the land has been raised up through isostatic uplift or tectonic movements.

在诸如冰川期末期，随着气温上升，冰川重量移除，陆地的均衡上升就发生了。在后冰川期，均衡上升影响了诸多海岸线，如斯堪的纳维亚、苏格兰、阿拉斯加和纽芬兰的海岸线。

Isostatic uplift of the land occurs when the weight of ice is removed as temperatures rise, as at the end of an ice age; it has affected coastlines, for example, in Scandinavia, Scotland, Alaska, and Newfoundland during the postglacial period.

构造运动包括构成地壳的板块位移。地中海地区更新世中期和晚期的上升海滩就是板块位移的一项例证。

Tectonic movements involve displacements in the plates that make up Earth’s crust; Middle and Late Pleistocene raised beaches in the Mediterranean are one instance of such movements.

上升沙滩常常由沙地、卵石或沙丘区域组成，有时还包含海贝或者残骸堆，残骸堆里有人类用过的海洋动物的贝壳和骨头。

Raised beaches often consist of areas of sand, pebbles, or dunes, sometimes containing seashells or piles of debris comprising shells and bones of marine animals used by humans.

例如，在东京港，日本新石器时代（约公元前10000到300年）的贝丘标出了海水最高期（6500-5500年前）海岸线的位置。当时，经过构造运动，海洋与当今的日本大陆相比要高出三到五米。

In Tokyo Bay, for example, shell mounds of the Jomon period (about 10,000 to 300 B.C.E.) mark the position of the shoreline at a time of maximum inundation by the sea (6,500–5,500 years ago), when, through tectonic movement, the sea was three to five meters higher in relation to the contemporary landmass of Japan than at present.

对贝壳的分析证实了海洋地形的变化，因为只有在最高期软体动物生存的亚热带物种才会出现，这表明当时的水温更高。

Analysis of the shells themselves has confirmed the changes in marine topography, for it is only during the maximum phase that subtropical species of mollusc are present, indicating a higher water temperature.

The word “crucial” in the passage is closest in meaning to

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.

Which of the following can be inferred from paragraph 2 about the effects of climate change during the Paleolithic period?

By indicating that flora and fauna of isolated or insular areas were often “irreversibly affected” by the changes due to the Ice Age, the author means that the flora and fauna were

The word “remnants” in the passage is closest in meaning to

According to paragraph 3, why is the height of a raised beach not a straightforward indicator of past sea level?

According to paragraph 3, which of the following causes an isostatic uplift?

Which of the following can be inferred from paragraph 4 about Tokyo Bay?

Look at the four squares  that indicate where the following sentence could be added to the passage. The location of these heaps of rubbish can be an accurate indicator of earlier coastlines.  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.

Ancient Coastlines Information on past climates is primarily of relevance to archaeology because of what it tells us about the effects on the land and on the resources that people needed to survive. The most crucial effect of climate was on the sheer quantity of land available in each period, measurable by studying ancient coastlines. These have changed constantly through time, even in relatively recent periods, as can be seen from the Neolithic stone circle of Er Lannic, in Brittany, France (once inland but now half submerged on an island) or medieval villages in east Yorkshire, England, that have tumbled into the sea in the last few centuries as the North Sea gnaws its way westward and erodes the cliffs. Conversely, silts deposited by rivers sometimes push the sea farther back, creating new land, as at Ephesus in western Turkey, a port on the coast in Roman times but today some five kilometers inland. Nevertheless, for archaeologists concerned with the long periods of time of the Paleolithic period there are variations in coastlines of much greater magnitude to consider. The expansion and contraction of the continental glaciers caused huge and uneven rises and falls in sea levels worldwide. When the ice sheets grew, the sea level would drop as water became locked up in the glaciers; when the ice melted, the sea level would rise again. Falls in sea level often exposed a number of important land bridges, such as those linking Alaska to northeast Asia and Britain to northwest Europe, a phenomenon with far-reaching effects not only on human colonization of the globe but also on the environment as a whole—the flora and fauna of isolated or insular areas were radically and often irreversibly affected. Between Alaska and Asia today lies the Bering Strait, which is so shallow that a fall in sea level of only four meters would turn it into a land bridge. When the ice sheets were at their greatest extent some 18,000 years ago (the glacial maximum), it is thought that the fall was about 120 meters, which therefore created not merely a bridge but a vast plain, 1,000 kilometers from the north to the south, which has been called Beringia. The existence of Beringia (and the extent to which it could have supported human life) is one of the crucial pieces of evidence in the continuing debate about the likely route and date of human colonization of the New World. The assessment of past rises and falls in sea level requires study of submerged land surfaces off the coast and of raised or elevated beaches on land. Raised beaches are remnants of former coastlines at higher levels relative to the present shoreline and visible, for instance, along the Californian coast north of San Francisco. The height of a raised beach above the present shoreline, however, does not generally give a straightforward indication of the height of a former sea level. In the majority of cases, the beaches lie at a higher level because the land has been raised up through isostatic uplift or tectonic movements. Isostatic uplift of the land occurs when the weight of ice is removed as temperatures rise, as at the end of an ice age; it has affected coastlines, for example, in Scandinavia, Scotland, Alaska, and Newfoundland during the postglacial period. Tectonic movements involve displacements in the plates that make up Earth’s crust; Middle and Late Pleistocene raised beaches in the Mediterranean are one instance of such movements. Raised beaches often consist of areas of sand, pebbles, or dunes, sometimes containing seashells or piles of debris comprising shells and bones of marine animals used by humans.  In Tokyo Bay, for example, shell mounds of the Jomon period (about 10,000 to 300 B.C.E.) mark the position of the shoreline at a time of maximum inundation by the sea (6,500–5,500 years ago), when, through tectonic movement, the sea was three to five meters higher in relation to the contemporary landmass of Japan than at present.  Analysis of the shells themselves has confirmed the changes in marine topography, for it is only during the maximum phase that subtropical species of mollusc are present, indicating a higher water temperature.