今日词汇题汇总如下：

第一篇：

　　内容：Gliding和soaring

　　上来先说鸟飞行的时候有gliding，但是soaring时的气流上升会比gliding更快，然后举了一个鸟的例子。

后面写两种产生上升求流的过程，当局部空气热了会产生thermal，热空气上升后会被冷空气替补，然后会形成一系列的上升空气，但是有关形状大家有分歧，但是有人认为只有ring状的会是持续的。当上升速度比下降速度快的时候，会上升，鸟会利用这个循环来飞。

解析：本文属于描述型文章，从机经来看，在部分段落有流程写作形式，而且学科词汇偏多，在阅读时学生需要先解决gliding和soaring这两个不同术语的意思，随后还需要在流程阅读时弄清楚不同阶段以及形成条件或者特征。本话题在TPO中不常见，但是类似的流程结构可以参考TPO18的lighting和TPO15的Glacier Formation.

参考阅读：

Lightning

Lightning is a brilliant flash of light produced by an electrical discharge from a storm cloud. The electrical discharge takes place when the attractive tension between a region of negatively charged particles and a region of positively charged particles becomes so great that the charged particles suddenly rush together. The coming together of the oppositely charged particles neutralizes the electrical tension and releases a tremendous amount of energy, which we see as lightning. The separation of positively and negatively charged particles takes place during the development of the storm cloud.

The separation of charged particles that forms in a storm cloud has a sandwich-like structure. Concentrations of positively charged particles develop at the top and bottom of the cloud, but the middle region becomes negatively charged. Recent measurements made in the field together with laboratory simulations offer a promising explanation of how this structure of charged particles forms. What happens is that small (millimeter-to centimeter-size) pellets of ice form in the cold upper regions of the cloud. When these ice pellets fall, some of them strike much smaller ice crystals in the center of the cloud. The temperature at the center of the cloud is about -15℃ or lower. At such temperatures, the collision between the ice pellets and the ice crystals causes electrical charges to shift so that the ice pellets acquire a negative charge and the ice crystals become positively charged. Then updraft wind currents carry the light, positively charged ice crystals up to the top of the cloud. The heavier negatively charged ice pellets are left to concentrate in the center. This process explains why the top of the cloud becomes positively charged, while the center becomes negatively charged. The negatively charged region is large: several hundred meters thick and several kilometers in diameter. Below this large, cold, negatively charged region, the cloud is warmer than -15℃, and at these temperatures, collisions between ice crystals and falling ice pellets produce positively charged ice pellets that then populate a small region at the base of the cloud.

Most lightning takes place within a cloud when the charge separation within the cloud collapses. However, as the storm cloud develops, the ground beneath the cloud becomes positively charged and lightning can take place in the form of an electrical discharge between the negative charge of the cloud and the positively charged ground. Lightning that strikes the ground is the most likely to be destructive, so even though it represents only 20 percent of all lightning, it has received a lot of scientific attention.

Using high-speed photography, scientists have determined that there are two steps to the occurrence of lightning from a cloud to the ground. First, a channel, or path, is formed that connects the cloud and the ground. Then a strong current of electrons follows that path from the cloud to the ground, and it is that current that illuminates the channel as the lightning we see.

The formation of the channel is initiated when electrons surge from the cloud base toward the ground. When a stream of these negatively charged electrons comes within 100 meters of the ground it is met by a stream of positively charged particles that comes up from the ground. When the negatively and positively charged streams meet, a complete channel connecting the cloud and the ground is formed. The channel is only a few centimeters in diameter, but that is wide enough for electrons to follow the channel to the ground in the visible form of a flash of lightning. The stream of positive particles that meets the surge of electrons from the cloud often arises from a tall pointed structure such as a metal flagpole or a tower. That is why the subsequent lightning that follows the completed channel often strikes a tall structure.

Once a channel has been formed, it is usually used by several lightning discharges, each of them consisting of a stream of electrons from the cloud meeting a stream of positive particles along the established path. Sometimes, however, a stream of electrons following an established channel is met by a positive stream making a new path up from the ground. The result is a forked lightning that strikes the ground in two places.

第二篇：

　　内容：中世纪的欧洲

　　土地管理方法和农业技术改进导致欧洲农产品产量增加，一个改变是从两田的那种轮耕方式变成了三田的，能够利用更多的土地，另外一个改变是使用动物来耕地，能够让土壤更好，后面写了发明了一种新的设备，放在了动物不同的地方，这时候马可以用来耕地，然后带来更多好处。更多的粮食使得有了更多的贸易，然后产生了城镇，然后在各种贸易下，发展了市场，改变了人们的生活方式。

　  解析：本文属于因果型文章，但是结构略微复杂，从机经来前半篇文章写的是原因，后半篇文章写的是影响，不过因果型文章一般主旨句都比较明确，在阅读时学员可以参考TPO33的First Civilization.

   参考阅读：

The First Civilizations

Evidence suggests that an important stimulus behind the rise of early civilizations was the development of settled agriculture, which unleashed a series of changes in the organization of human communities that culminated in the rise of large ancient empires.

The exact time and place that crops were first cultivated successfully is uncertain. Many prehistorians believe that farming may have emerged in dependently in several different areas of the world when small communities, driven by increasing population and a decline in available food resources, began to plant seeds in the ground in an effort to guarantee their survival. The first farmers, who may have lived as long as 10,000 years ago, undoubtedly used simple techniques and still relied primarily on other forms of food production, such as hunting, foraging, or pastoralism. The real breakthrough took place when farmers began to cultivate crops along the floodplains of river systems. The advantage was that crops grown in such areas were not as dependent on rainfall and therefore produced a more reliable harvest. An additional benefit was that the sediment carried by the river waters deposited nutrients in the soil, thus enabling the farmer to cultivate a single plot of ground for many years without moving to a new location. Thus, the first truly sedentary (that is, nonmigratory) societies were born. As time went on, such communities gradually learned how to direct the flow of water to enhance the productive capacity of the land, while the introduction of the iron plow eventually led to the cultivation of heavy soils not previously susceptible to agriculture.

The spread of this river valley agriculture in various parts of Asia and Africa was the decisive factor in the rise of the first civilizations. The increase in food production in these regions led to a significant growth in population, while efforts to control the flow of water to maximize the irrigation of cultivated areas and to protect the local inhabitants from hostile forces outside the community provoked the first steps toward cooperative activities on a large scale. The need to oversee the entire process brought about the emergence of an elite that was eventually transformed into a government.

The first clear steps in the rise of the first civilizations took place in the fourth and third millennia B.C. in Mesopotamia, northern Africa, India, and China. How the first governments took shape in these areas is not certain, but anthropologists studying the evolution of human communities in various parts of the world have discovered that one common stage in the process is the emergence of what are called “big men” within a single village or a collection of villages. By means of their military prowess, dominant personalities, or political talents, these people gradually emerge as the leaders of that community. In time, the “big men” become formal symbols of authority and pass on that authority to others within their own family. As the communities continue to grow in size and material wealth, the “big men” assume hereditary status, and their allies and family members are transformed into a hereditary monarchy.

The appearance of these sedentary societies had a major impact on the social organizations, religious beliefs, and way of life of the peoples living within their boundaries. With the increase in population and the development of centralized authority came the emergence of the cities.While some of these urban centers were identified with a particular economic function, such as proximity to gold or iron deposits or a strategic location on a major trade route, others served primarily as administrative centers or the site of temples for the official cult or other ritual observances. Within these cities, new forms of livelihood appeared to satisfy the growing need for social services and consumer goods. Some people became artisans or merchants, while others became warriors, scholars, or priests. In some cases, the physical division within the first cities reflected the strict hierarchical character of the society as a whole, with a royal palace surrounded by an imposing wall and separate from the remainder of the urban population. In other instances, such as the Indus River Valley, the cities lacked a royal precinct and the ostentatious palaces that marked their contemporaries elsewhere.

第三篇：

 内容：讲的是大型动物灭绝。各个地方灭绝的情况还不一样，科学家提出了以细节问题，有except题。有两种说法，一是climate，一是认为hunt。花了两三段反驳climate。1是动物并不是移去更温暖的地方，而是移去稍微不那么暖和地方2是讲之前也有类似climate变化，但没有灭绝。(原因是两种)后面反驳hunt，hunt里面有对比，和另一个地方有人类，但没有灭绝是因为动物已经适应，而这边没有适应，所以灭绝。反驳有三点好像，1.人类居住是很少人聚集，不足以杀掉动物2.待定3.讲遗留下来的东西并没有很多人hunt的踪迹好像，还没有动物被捕杀的痕迹。最后一段总数，估计是要很多混合来看。

解析：本文属于典型的问题解决型的文章，关注的是动物灭绝的原因，该类型的结构在TPO中特别常见。一般问题解决型文章的展开方式都是通过多个理论展开，而且多把注意力放在理论的缺陷部分，从机经来判断，本文的主要题目也多关注两个理论的缺陷方面。有关背景的相关知识可以参考TPO15的Mass Extinction以及TPO8的The Extinction of Dinosaurs.

参考阅读：

Extinction of the Dinosaurs

Paleozoic Era 334 to 248 million years ago

Mesozoic Era 245 to 65 million years ago

—Triassic Period

—Jurassic Period

—Cretaceous Period

Cenozoic Era 65 million years ago to the present

Paleontologists have argued for a long time that the demise of the dinosaurs was caused by climatic alterations associated with slow changes in the positions of continents and seas resulting from plate tectonics. Off and on throughout the Cretaceous (the last period of the Mesozoic era, during which dinosaurs flourished), large shallow seas covered extensive areas of the continents. Data from diverse sources, including geochemical evidence preserved in seafloor sediments, indicate that the Late Cretaceous climate was milder than today’s. The days were not too hot, nor the nights too cold. The summers were not too warm, nor the winters too frigid. The shallow seas on the continents probably buffered the temperature of the nearby air, keeping it relatively constant.

At the end of the Cretaceous, the geological record shows that these seaways retreated from the continents back into the major ocean basins. No one knows why. Over a period of about 100,000 years, while the seas pulled back, climates around the world became dramatically more extreme: warmer days, cooler nights; hotter summers, colder winters. Perhaps dinosaurs could not tolerate these extreme temperature changes and became extinct.

If true, though, why did cold-blooded animals such as snakes, lizards, turtles, and crocodiles survive the freezing winters and torrid summers? These animals are at the mercy of the climate to maintain a livable body temperature. It’s hard to understand why they would not be affected, whereas dinosaurs were left too crippled to cope, especially if, as some scientists believe, dinosaurs were warm-blooded. Critics also point out that the shallow seaways had retreated from and advanced on the continents numerous times during the Mesozoic, so why did the dinosaurs survive the climatic changes associated with the earlier fluctuations but not with this one? Although initially appealing, the hypothesis of a simple climatic change related to sea levels is insufficient to explain all the data.

Dissatisfaction with conventional explanations for dinosaur extinctions led to a surprising observation that, in turn, has suggested a new hypothesis. Many plants and animals disappear abruptly from the fossil record as one moves from layers of rock documenting the end of the Cretaceous up into rocks representing the beginning of the Cenozoic (the era after the Mesozoic). Between the last layer of Cretaceous rock and the first layer of Cenozoic rock, there is often a thin layer of clay. Scientists felt that they could get an idea of how long the extinctions took by determining how long it took to deposit this one centimeter of clay and they thought they could determine the time it took to deposit the clay by determining the amount of the element iridium (Ir) it contained.

Ir has not been common at Earth’s since the very beginning of the planet’s history. Because it usually exists in a metallic state, it was preferentially incorporated in Earth’s core as the planet cooled and consolidated. Ir is found in high concentrations in some meteorites, in which the solar system’s original chemical composition is preserved. Even today, microscopic meteorites continually bombard Earth, falling on both land and sea. By measuring how many of these meteorites fall to Earth over a given period of time, scientists can estimate how long it might have taken to deposit the observed amount of Ir in the boundary clay. These calculations suggest that a period of about one million years would have been required. However, other reliable evidence suggests that the deposition of the boundary clay could not have taken one million years. So the unusually high concentration of Ir seems to require a special explanation.

In view of these facts, scientists hypothesized that a single large asteroid, about 10 to 15 kilometers across, collided with Earth, and the resulting fallout created the boundary clay. Their calculations show that the impact kicked up a dust cloud that cut off sunlight for several months, inhibiting photosynthesis in plants; decreased surface temperatures on continents to below freezing; caused extreme episodes of acid rain; and significantly raised long-term global temperatures through the greenhouse effect. This disruption of food chain and climate would have eradicated the dinosaurs and other organisms in less than fifty years.