2015年10月10日
10月10日托福阅读第一篇
题材划分： 历史发展史
主要内容：石器时代人们的生活
石器时代的人过着游牧的生活，他们的生活靠采集和狩猎，非常容易满足，他们的供大于求己经到了一个很极端的地步。他们不怎么在乎good的多少，因为他们时常需要迁徙。
其次有时候他们还会限制自己的需求。比如让reproduction的进程变缓慢。中间段讲为什么他们要迁移。因为变冷了，所以他们从高处往低处搬。他们为了食物四处收集，提高种类多样性。这个过程中，他们的食物什么的都是充足的。他们的工作时间很少，一天只有三到五个小时，如果可以吃饱就不干活了，娱乐的时间非常多。之后工作时间逐渐上升打了8.2小时后来又跌回8小时。石器时代的人和后来的人类以及现代的farmer相比较，他们的工作时间依旧是最少的，同样的，他们生病的机会也是最少的。和一些大的游牧部族相比小一点的游牧部族更free of disease characteristic of larger communities。
相似TPO练习推荐
TPO-7 Agriculture, Iron, and the Bantu Peoples
TPO-14 Pastoralism in Ancient Inner Eurasia
TPO-21 The Origins of Agriculture
相关背景知识：
A hunter-gatherer or early human society is one in which most or all food is obtained from wild plants and animals, in contrast to agricultural societies, which rely mainly on domesticated species.
Hunting and gathering was humanity's first and most successful adaptation, occupying at least 90 percent of human history, and 10,000 years ago, all humans lived this way.[2] Following the invention of agriculture, hunter-gatherers have been displaced or conquered by farming or pastoralist groups in most parts of the world.
Only a few contemporary societies are classified as hunter-gatherers, and many supplement their foraging activity with horticulture and/or keeping animals.
In the 1950s, Louis Binford suggested that early humans were obtaining meat via scavenging, not hunting. Early humans in the Lower Paleolithic lived in forests and woodlands, which allowed them to collect seafood, eggs, nuts, and fruits besides scavenging. Rather than killing large animals for meat, according to this view, they used carcasses of such animals that had either been killed by predators or that had died of natural causes.
According to the endurance running hypothesis, long-distance running as in persistence hunting, a method still practiced by some hunter-gatherer groups in modern times, was likely the driving evolutionary force leading to the evolution of certain human characteristics. This hypothesis does not necessarily contradict the scavenging hypothesis: both subsistence strategies could have been in use – sequentially, alternating or even simultaneously.
Hunting and gathering was presumably the subsistence strategy employed by human societies beginning some 1.8 million years ago, by Homo erectus, and from its appearance some 0.2 million years ago by Homo sapiens. It remained the only mode of subsistence until the end of the Mesolithic period some 10,000 years ago, and after this was replaced only gradually with the spread of the Neolithic Revolution.
Starting at the transition between the Middle to Upper Paleolithic period, some 80,000 to 70,000 years ago, some hunter-gatherers bands began to specialize, concentrating on hunting a smaller selection of (often larger) game and gathering a smaller selection of food. This specialization of work also involved creating specialized tools, like fishing nets and hooks and bone harpoons. The transition into the subsequent Neolithic period is chiefly defined by the unprecedented development of nascent agricultural practices. Agriculture originated and spread in several different areas including the Middle East, Asia, Mesoamerica, and the Andes beginning as early as 12,000 years ago.
Forest gardening was also being used as a food production system in various parts of the world over this period. Forest gardens originated in prehistoric times along jungle-clad river banks and in the wet foothills of monsoon regions.[citation needed] In the gradual process of families improving their immediate environment, useful tree and vine species were identified, protected and improved, whilst undesirable species were eliminated. Eventually superior foreign species were selected and incorporated into the gardens.
Many groups continued their hunter-gatherer ways of life, although their numbers have continually declined, partly as a result of pressure from growing agricultural and pastoral communities. Many of them reside in the developing world, either in arid regions or tropical forests. Areas that were formerly available to hunter-gatherers were—and continue to be—encroached upon by the settlements of agriculturalists. In the resulting competition for land use, hunter-gatherer societies either adopted these practices or moved to other areas. In addition, Jared Diamond has blamed a decline in the availability of wild foods, particularly animal resources. In North and South America, for example, most large mammal species had gone extinct by the end of the Pleistocene—according to Diamond, because of overexploitation by humans, although the overkill hypothesis he advocates is strongly contested.[by whom?]
As the number and size of agricultural societies increased, they expanded into lands traditionally used by hunter-gatherers. This process of agriculture-driven expansion led to the development of the first forms of government in agricultural centers, such as the Fertile Crescent, Ancient India, Ancient China, Olmec, Sub-Saharan Africa and Norte Chico.
As a result of the now near-universal human reliance upon agriculture, the few contemporary hunter-gatherer cultures usually live in areas unsuitable for agricultural use.
Archaeologists can use evidence such as stone tool use to track hunter-gatherer activities, including mobility.
第二篇
题材划分： 生态环境
主要内容：洋流的形成
海水在季风和地转偏向力的作用下产生洋流。洋流分为上下两层。温暖密度小,下层含盐多密度大，这两层各自流动不混合。
带着温暖海水向两极流动，在极地地区变冷，结冰使得盐分析出,密度变大而下层成为洋流。下层洋流流回赤道。.
两层混合的地方发生海岸平行的地方,这里的风向在地转偏向力的作用下把上层洋流推离海岸,于是下层洋流向上补充。洋流混合对生态有很大作用，因为把海洋生物死亡后沉到下层然后被分解的营养带到上层。滋养植物-浮游生物-更高级消费者。
洋流对流经的地区的气候有重要影响。
洋流还与全球气候变暖联系在一起。因为二氧化碳可以溶在海水，然后沉淀到海底。
相似TPO练习推荐：
TPO-15 Glacier Formation
相关知识背景：
Surface oceanic currents are sometimes wind driven and develop their typical clockwise spirals in the northern hemisphere and counterclockwise rotation in the southern hemisphere because of imposed wind stresses. In wind driven currents, the Ekman spiral effect results in the currents flowing at an angle to the driving winds. The areas of surface ocean currents move somewhat with the seasons; this is most notable in equatorial currents.
Ocean basins generally have a non-symmetric surface current, in that the eastern equatorward-flowing branch is broad and diffuse whereas the western poleward flowing branch is very narrow. These western boundary currents (of which the Gulf Stream is an example) are a consequence of the rotation of the Earth.
Deep ocean currents are driven by density and temperature gradients. Thermohaline circulation is also known as the ocean's conveyor belt (which refers to deep ocean density driven ocean basin currents). These currents, called submarine rivers, flow under the surface of the ocean and are hidden from immediate detection. Where significant vertical movement of ocean currents is observed, this is known as upwelling and downwelling. Deep ocean currents are currently being researched using a fleet of underwater robots called Argo.
The South Equatorial Currents of the Atlantic and Pacific straddle the equator. Though the Coriolis effect is weak near the equator (and absent at the equator), water moving in the currents on either side of the equator is deflected slightly poleward and replaced by deeper water. Thus, equatorial upwelling occurs in these westward flowing equatorial surface currents. Upwelling is an important process because this water from within and below the pycnocline is often rich in the nutrients needed by marine organisms for growth. By contrast, generally poor conditions for growth prevail in most of the open tropical ocean because strong layering isolates deep, nutrient rich water from the sunlit ocean surface.
Surface currents make up only 8% of all water in the ocean, are generally restricted to the upper 400 m (1,300 ft) of ocean water, and are separated from lower regions by varying temperatures and salinity which affect the density of the water, which in turn, defines each oceanic region. Because the movement of deep water in ocean basins is caused by density driven forces and gravity, deep waters sink into deep ocean basins at high latitudes where the temperatures are cold enough to cause the density to increase.
Ocean currents are measured in sverdrup (sv), where 1 sv is equivalent to a volume flow rate of 1,000,000 m3 (35,000,000 cu ft) per second.
Surface currents are found on the surface of an ocean, and are driven by large scale wind currents. They are directly affected by the wind—the Coriolis effect plays a role in their behaviors.
读第三篇
题材划分： 天文类
主要内容： 太阳大气
太阳大气反应了太阳系形成初期的成分构成，但地球现在的大气与那时显著不同。原始大气在太阳风和陨石的作用下被剥离地球，然后地球的火山的排气作用(outgassing )形成了现在大气的各种主要成分，但不包括氧气。相较现在20%的 氧气,一开始地球只有很少量的氧气。这些氧气主要是大气中的水发生光解作用(photosynthesis )产生的。氧气和海洋里的铁发生氧化，会沉淀到海底，氧气多的是其形成红色的氧化铁，少的时候形成黑色的，于是海底有些石头就会呈现带状。地球上的氧气还会变成臭氧，臭氧可以阻挡紫外线保护上的生命，臭氧在某个时间段内增加，在差不多结束的那段有个生命形式的爆发。
相似TPO练习推荐：
TPO-16 Planets in Our Solar System
Tpo25 The surface of Mars
相关知识背景：
During a total solar eclipse, when the disk of the Sun is covered by that of the Moon, the Sun's surrounding atmosphere can be seen. It is composed of three distinct parts the chromosphere, the transition region, the corona, that, together, form the heliosphere.
The coolest layer of the Sun is a temperature minimum region about 500 km above the photosphere, with a temperature of about 4,100 K. This part of the Sun is cool enough to allow the existence of simple molecules such as carbon monoxide and water, which can be detected via their absorption spectra.
The chromosphere, transition region, and corona are much hotter than the surface of the Sun. The reason is not well understood, but evidence suggests that Alfvén waves may have enough energy to heat the corona.
Above the temperature minimum layer is a layer about 2,000 km thick, dominated by a spectrum of emission and absorption lines. It is called the chromosphere from the Greek root chroma, meaning color, because the chromosphere is visible as a colored flash at the beginning and end of total solar eclipses. The temperature in the chromosphere increases gradually with altitude, ranging up to around 20,000 K near the top. In the upper part of the chromosphere helium becomes partially ionized.
Taken by Hinode's Solar Optical Telescope on 12 January 2007, this image of the Sun reveals the filamentary nature of the plasma connecting regions of different magnetic polarity.
Above the chromosphere, in a thin (about 200 km) transition region, the temperature rises rapidly from around 20,000 K in the upper chromosphere to coronal temperatures closer to 1,000,000 K. The temperature increase is facilitated by the full ionization of helium in the transition region, which significantly reduces radiative cooling of the plasma. The transition region does not occur at a well-defined altitude. Rather, it forms a kind of nimbus around chromospheric features such as spicules and filaments, and is in constant, chaotic motion. The transition region is not easily visible from Earth's surface, but is readily observable from space by instruments sensitive to the extreme ultraviolet portion of the spectrum.
The corona is the next layer of the Sun. The low corona, near the surface of the Sun, has a particle density around 1015 m3 to 1016 m3.The average temperature of the corona and solar wind is about 1,000,000–2,000,000 K; however, in the hottest regions it is 8,000,000–20,000,000 K.Although no complete theory yet exists to account for the temperature of the corona, at least some of its heat is known to be from magnetic reconnection.The corona is the extended atmosphere of the Sun, which has a volume much larger than the volume enclosed by the Sun's photosphere. A flow of plasma outward from the Sun into interplanetary space is the solar wind.
The heliosphere, the tenuous outermost atmosphere of the Sun, is filled with the solar wind plasma. This outermost layer of the Sun is defined to begin at the distance where the flow of the solar wind becomes superalfvénic—that is, where the flow becomes faster than the speed of Alfvén waves,at approximately 20 solar radii (0.1 AU). Turbulence and dynamic forces in the heliosphere cannot affect the shape of the solar corona within, because the information can only travel at the speed of Alfvén waves. The solar wind travels outward continuously through the heliosphere, forming the solar magnetic field into a spiral shape, until it impacts the heliopause more than 50 AU from the Sun. In December 2004, the Voyager 1 probe passed through a shock front that is thought to be part of the heliopause. Both of the Voyager probes have recorded higher levels of energetic particles as they approach the boundary.
相关推荐:
