考试日期：2014年5月24日

Reading Passage 1

Title:

苏美尔人

Question types:

文章内容回顾：

主题：历史文化类话题

本文讲述了苏美尔文明。苏美尔人的居住地土壤贫瘠，但是每年的洪水泛滥留下了肥沃的淤泥用来耕作，繁荣来自农业生产力的提高。由此产生了统治阶级，后来统治阶级组织农民工作，但是S地区除了农业再无其他优势，所以要开展贸易。他们的生活都是围绕temple展开，而统治阶层为了记录管理情况逐渐发明楔形文字。

难度分析：

苏美尔文明是托福常考的古代文明之一，阅读量较大的同学应该对这一背景和题材并不陌生。考生要善于抓住历史演进的主线，把握文明发展的进程，特别注意细节题的一一对应。

相关背景内容：

Sumer was the southernmost region of ancient Mesopotamia (modern-day Iraq and Kuwait) which is generally considered the cradle of civilization. The name comes from Akkadian, the language of the north of Mesopotamia, and means “land of the civilized kings”. The Sumerians called themselves “the black headed people” and their land, in cuneiform script, was simply “the land” or “the land of the black headed people”. In the biblical Book of Genesis Sumer is known as Shinar. According to the Sumerian King List, when the gods first gave human beings the gifts necessary for cultivating society, they did so by establishing the city of Eridu in the region of Sumer. While the Sumerian city of Uruk is held to be the oldest city in the world, the ancient Mesopotamians believed that it was Eridu and that it was here that order was established and civilization began.

The Ubaid Period

The region of Sumer was long thought to have been first inhabited around 4500 BCE. This date has been contested in recent years, however, and it now thought that human activity in the area began much earlier. The first settlers were not Sumerians but a people of unknown origin whom archaeologists have termed the Ubaid people (from the excavated mound of al-Ubaid where the artifacts were uncovered which first attested to their existence) or the Proto-Euphrateans (which designates them as earlier inhabitants of the region of the Euphrates River). Whoever these people were, they had already moved from a hunter-gatherer society to an agrarian one prior to 5000 BCE. Excavations from al-Ubaid and other sites throughout southern Iraq have uncovered stone tools from the Ubaid people such as hoes, knives, and adzes and clay artifacts which included sickles, bricks, painted pottery, and figurines. These people were the first agents of civilization in the region. At what point the people who came to be known as Sumerians entered the area is not known.

The Sumerian King List

According to the Sumerian scholar Samuel Noah Kramer, “The first ruler of Sumer, whose deeds are recorded, if only in the briefest kind of statement, is a king by the name of Etana of Kish, who may have come to the throne quite early in the third millennium B.C. In the King List he is described as `he who stabilized all the lands’.” The Sumerian King List is a cuneiform document, written by a scribe of the city of Lagash, sometime around 2100 BCE which lists all of the kings of the region, and their accomplishments, in an attempt to show continuity of order in society dating back to the beginning of civilization. As the Mesopotamians generally, and the Sumerians specifically, believed that civilization was the result of the gods’ triumph of order over chaos, the King List is thought to have been created to legitimize the reign of a king named Utu-Hegal of Uruk (who ruled c. 2100 BCE) by showing him as the most recent in a long line of rulers of the region. Etana is famous from the myth of the man who ascends to heaven on the back of an eagle and, like other kings mentioned in the list (Dumuzi and Gilgamesh among them) was known for superhuman feats and heroism. Utu-Hegal, it is thought, was trying to link himself to such earlier hero-kings through the creation of the King List.

The Rise of Cities

Whenever the Sumerian civilization was first established in the region, by 3600 BCE they had invented the wheel, writing, the sail boat, agricultural processes such as irrigation, and the concept of the city (though China and India also lay claim to `the first cities’ in the world). It is generally accepted that the first cities in the world rose in Sumer and, among the most important, were Eridu, Uruk, Ur, Larsa, Isin, Adab, Kullah, Lagash, Nippur, and Kish. The city of Uruk is held to be the first true city in the world. It has been noted, again by Kramer, that these names are not Sumerian but come from the Ubaid people and so were founded, at least as villages, much earlier than c. 5000 BCE. Other cities in Sumer were Sippar, Shuruppak, Bad-tibira, Girsu, Umma, Urukag, Nina, and Kissura. All were of varying size and scope with Uruk the largest and most powerful at its prime.

Reading Passage 2

Title:

恐龙灭绝

Question types:

文章内容回顾：

主题：生物类

本文讲述了恐龙灭绝的一个主要原因：小行星或彗星的撞击。最近有发现irrumlian在很多地方都有，因为这个元素只在陨石中存在，所以可以当做证据。后来又说撞击带来了很多影响，如温度下降，隔绝阳光。恐龙就灭绝了。但是rodent和其他一些小的哺乳动物存活了下来，因为他们住在地底下。

难度分析：

生物类话题是托福考试永恒的高频题，关于行星撞击与恐龙灭绝在TPO中更是多有出现。由于大多数考生在生物学方面词汇都有大量积累，对于恐龙灭绝的话题也相对熟悉，所以理解起来难度应该不会太大。

相关背景内容：

Sixty-five million years ago the last of the non-avian dinosaurs went extinct. So too did the giant mosasaurs and plesiosaurs in the seas and the pterosaurs in the skies. Plankton, the base of the ocean food chain, took a hard hit. Many families of brachiopods and sea sponges disappeared. The remaining hard-shelled ammonites vanished. Shark diversity shriveled. Most vegetation withered. In all, more than half of the world's species were obliterated.

What caused this mass extinction that marks the end of the Cretaceous and the beginning of the Paleogene? Scientists have yet to find an answer. The one that does must explain why these animals died while most mammals, turtles, crocodiles, salamanders, and frogs survived. Birds escaped. So did snails, bivalves, sea stars (starfish), and sea urchins. Even hardy plants able to weather climate extremes fared OK.

Scientists tend to huddle around one of two hypotheses that may explain the Cretaceous extinction: an extraterrestrial impact, such as an asteroid or comet, or a massive bout of volcanism. Either scenario would have choked the skies with debris that starved the Earth of the sun's energy, throwing a wrench in photosynthesis and sending destruction up and down the food chain. Once the dust settled, greenhouse gases locked in the atmosphere would have caused the temperature to soar, a swift climate swing to topple much of the life that survived the prolonged darkness.

Asteroid or Volcanoes?

The extraterrestrial impact theory stems from the discovery that a layer of rock dated precisely to the extinction event is rich in the metal iridium. This layer is found all over the world, on land and in the oceans. Iridium is rare on Earth but it's found in meteorites at the same concentration as in this layer. This led scientists to postulate that the iridium was scattered worldwide when a comet or asteroid struck somewhere on Earth and then vaporized. A 110-mile-wide (180-kilometer-wide) crater carved out of Mexico's Yucatán Peninsula, called Chicxulub, has since been found and dated to 65 million years ago. Many scientists believe the fallout from the impact killed the dinosaurs.

But Earth's core is also rich in iridium, and the core is the source of magma that some scientists say spewed out in vast, floodlike flows that piled up more than 1.5 miles (2.4 kilometers) thick over 1 million square miles (2.6 million square kilometers) of India. This bout of volcanism has also been dated to about 65 million years ago and would have spread the iridium around the world, along with sunlight-blocking dust and soot and greenhouse gases.

Both hypotheses have merit. Some scientists think both may have contributed to the extinction, and others suggest the real cause was a more gradual shift in climate and changing sea levels. Regardless of what caused the extinction, it marked the end of Tyrannosaurus rex's reign of terror and opened the door for mammals to rapidly diversify and evolve into newly opened niches.

Reading Passage 3

Title:

冰河时期

Question types:

文章内容回顾：

主题：地质类话题

本文讲解了冰河时期形成的原因。有人提出造成冰川的三个原因，分别是地球轨道的形状；地轴的角度；地球的wobbal，他们只会改变平均水平，当冬天和夏天变温和的时候，冰川就形成了。别人质疑他，因为地球会这样不断周期变化，因此冰川就会按周期产生，但冰川并没有这样频繁。得出结论应该还有别的因素影响，比如火山灰进入大气层，二氧化碳减少，太阳辐射量减少，后来发现二氧化碳比较可信。

难度分析：

地质学是托福听力考试中的常见话题，是关于地球的物质组成、内部构造、外部特征、各层圈之间的相互作用和演变历史的知识体系，是研究地球本身的学科。地理学描述和分析发生在地球表面上的自然、生物和人文现象的空间变化，探讨它们之间的相互关系及其重要的区域类型。

相关背景内容：

Causes of ice ages

Variations in Earth's orbit (Milankovitch cycles)

The Milankovitch cycles are a set of cyclic variations in characteristics of the Earth's orbit around the Sun. Each cycle has a different length, so at some times their effects reinforce each other and at other times they (partially) cancel each other.

Past and future of daily average insolation at top of the atmosphere on the day of the summer solstice, at 65 N latitude.

There is strong evidence that the Milankovitch cycles affect the occurrence of glacial and interglacial periods within an ice age. The present ice age is the most studied and best understood, particularly the last 400,000 years, since this is the period covered by ice cores that record atmospheric composition and proxies for temperature and ice volume. Within this period, the match of glacial/interglacial frequencies to the Milanković orbital forcing periods is so close that orbital forcing is generally accepted. The combined effects of the changing distance to the Sun, the precession of the Earth's axis, and the changing tilt of the Earth's axis redistribute the sunlight received by the Earth. Of particular importance are changes in the tilt of the Earth's axis, which affect the intensity of seasons. For example, the amount of solar influx in July at 65 degrees north latitude varies by as much as 22% (from 450 W/m² to 550 W/m²). ts that cyclic changes in the Earth's orbital elements can be expressed in the glaciation record, additional explanations are necessary to explain which cycles are observed to be most important in the timing of glacial–interglacial periods. In particular, during the last 800,000 years, the dominant period of glacial–interglacial oscillation has been 100,000 years, which corresponds to changes in Earth's orbital eccentricity and orbital inclination. Yet this is by far the weakest of the three frequencies predicted by Milankovitch. During the period 3.0–0.8 million years ago, the dominant pattern of glaciation corresponded to the 41,000-year period of changes in Earth's obliquity (tilt of the axis). The reasons for dominance of one frequency versus another are poorly understood and an active area of current research, but the answer probably relates to some form of resonance in the Earth's climate system.

The "traditional" Milankovitch explanation struggles to explain the dominance of the 100,000-year cycle over the last 8 cycles. Richard A. Muller, Gordon J. F. MacDonald, and others have pointed out that those calculations are for a two-dimensional orbit of Earth but the three-dimensional orbit also has a 100,000-year cycle of orbital inclination. They proposed that these variations in orbital inclination lead to variations in insolation, as the Earth moves in and out of known dust bands in the solar system. Although this is a different mechanism to the traditional view, the "predicted" periods over the last 400,000 years are nearly the same. The Muller and MacDonald theory, in turn, has been challenged by Jose Antonio Rial.

Another worker, William Ruddiman, has suggested a model that explains the 100,000-year cycle by the modulating effect of eccentricity (weak 100,000-year cycle) on precession (26,000-year cycle) combined with greenhouse gas feedbacks in the 41,000- and 26,000-year cycles. Yet another theory has been advanced by Peter Huybers who argued that the 41,000-year cycle has always been dominant, but that the Earth has entered a mode of climate behavior where only the second or third cycle triggers an ice age. This would imply that the 100,000-year periodicity is really an illusion created by averaging together cycles lasting 80,000 and 120,000 years. This theory is consistent with a simple empirical multi-state model proposed by Didier Paillard. Paillard suggests that the late Pleistocene glacial cycles can be seen as jumps between three quasi-stable climate states. The jumps are induced by the orbital forcing, while in the early Pleistocene the 41,000-year glacial cycles resulted from jumps between only two climate states. A dynamical model explaining this behavior was proposed by Peter Ditlevsen. This is in support of the suggestion that the late Pleistocene glacial cycles are not due to the weak 100,000-year eccentricity cycle, but a non-linear response to mainly the 41,000-year obliquity cycle.