第一篇 First Eye
相关背景学习：
Fossils (from Classical Latin fossilis; literally, "obtained by digging") are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous (fossil-containing) rock formations and sedimentary layers (strata) is known as the fossil record.
The study of fossils across geological time, how they were formed, and the evolutionary relationships between taxa (phylogeny) are some of the most important functions of the science of paleontology. Such a preserved specimen is called a "fossil" if it is older than some minimum age, most often the arbitrary date of 10,000 years. Hence, fossils range in age from the youngest at the start of the Holocene Epoch to the oldest from the Archaean Eon, up to 3.48 billion years old. The observation that certain fossils were associated with certain rock strata led early geologists to recognize a geological timescale in the 19th century. The development of radiometric dating techniques in the early 20th century allowed geologists to determine the numerical or "absolute" age of the various strata and thereby the included fossils.
Like extant organisms, fossils vary in size from microscopic, even single bacterial cells one micrometer in diameter, to gigantic, such as dinosaurs and trees many meters long and weighing many tons. A fossil normally preserves only a portion of the deceased organism, usually that portion that was partially mineralized during life, such as the bones and teeth of vertebrates, or the chitinous or calcareous exoskeletons of invertebrates. Fossils may also consist of the marks left behind by the organism while it was alive, such as animal tracks or feces (coprolites). These types of fossil are called trace fossils (or ichnofossils), as opposed to body fossils. Finally, past life leaves some markers that cannot be seen but can be detected in the form of biochemical signals; these are known as chemofossils or biomarkers.
第二篇 地球大气的形成
相关背景学习：The atmosphere of Earth
The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation).
The common name given to the atmospheric gases used in breathing and photosynthesis is air. By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere. Although air content and atmospheric pressure vary at different layers, air suitable for the survival of terrestrial plants and terrestrial animals currently is only known to be found in Earth's troposphere and artificial atmospheres.
The atmosphere has a mass of about 5.15×1018 kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. The Kármán line, at 100 km (62 mi), or 1.57% of Earth's radius, is often used as the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi). Several layers can be distinguished in the atmosphere, based on characteristics such as temperature and composition.
The study of Earth's atmosphere and its processes is called atmospheric science (aerology). Early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann.
第三篇 文明的形成
解析：历史发展类的文章。按照时间顺序进行解读，注意段落之间的联系。
相关背景学习：civilization
A civilization (US) or civilisation (UK) is any complex state society characterized by urban development, social stratification, symbolic communication forms (typically, writing systems), and a perceived separation from and domination over the natural environment. Civilizations are intimately associated with and often further defined by other socio-politico-economic characteristics, including centralization, the domestication of both humans and other organisms, specialization of labor, culturally ingrained ideologies of progress and supremacism, monumental architecture, taxation, societal dependence upon agriculture, and expansionism. Historically, a civilization was an "advanced" culture in contrast to more supposedly barbarian, savage, or primitive cultures. In this broad sense, a civilization contrasts with non-centralized feudal or tribal societies, including the cultures of nomadic pastoralists or hunter-gatherers. As an uncountable noun, civilization also refers to the process of a society developing into a centralized, urbanized, stratified structure.
Civilizations are organized in densely populated settlements divided into hierarchical social classes with a ruling elite and subordinate urban and rural populations, which, by the engagement in intensive agriculture, mining, small-scale manufacture and trade. Civilization concentrates power, extending human control over the rest of nature, including over other human beings.
The earliest emergence of civilizations is generally associated with the final stages of the Neolithic Revolution, culminating in the relatively rapid process of state formation, a political development associated with the appearance of a governing elite. This neolithic technology and lifestyle was established first in the Middle East (for example at Gbekli Tepe, from about 9,130 BCE), and Yangtze and later in the Yellow river basin in China (for example the Pengtoushan culture from 7,500 BCE), and later spread. But similar "revolutions" also began independently from 9,000 years ago in such places as the Norte Chico civilization in Peru and Mesoamerica at the Balsas River. These were among the six civilizations worldwide that arose independently. The neolithic revolution in turn was dependent upon the development of sedentarism, the domestication of grains and animals and the development lifestyles which allowed economies of scale and the accumulation of surplus production by certain social sectors. The transition from "complex chieftains" to "civilisations", while still disputed, seems to be associated with the development of state structures, in which power was further monopolised by an elite
Towards the end of the Neolithic period, various Chalcolithic civilizations began to rise in various "cradles" from around 3300 BCE. Chalcolithic Civilizations, as defined above, also developed in Pre-Columbian Americas and, despite an early start in Egypt, Axum and Kush, much later in Iron Age sub-Saharan Africa. The Bronze Age collapse was followed by the Iron Age around 1200 BCE, during which a number of new civilizations emerged, culminating in the Axial Age transition to Classical civilization. A major technological and cultural transition to modernity began approximately 1500 CE in western Europe, and from this beginning new approaches to science and law spread rapidly around the world.
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