英语美文短篇欣赏
英语美文短篇欣赏
学习啦在线学习网 加强经典美文诵读与积累,并对学生加以写作指导,做到读写训练有效结合,能让学生有效地提高写作能力。小编精心收集了初中短篇英语美文，供大家欣赏学习!
初中短篇英语美文篇1
Population Growth
The growth of population during the past few centuries is no proof that population willcontinue to grow straight upward toward infinity and doom. On the contrary, demographichistory offers evidence that population growth has not been at all constant. According topaleoecologist Edward Deevey, the past million years show three momentous changes. Thefirst, a rapid increase in population around one million B. C., followed the innovations of toolmaking and tool using.But when the new power from the use of tools has been exploited,therate of world population growth fell and became almost stable. The next rapid jump inpopulation started perhaps 10,000 years ago, when mankind began to keep herds,plow andplant the earth. Once again when initial productivity gains had been absorbed, the rate ofpopulation growth abated. These two episodes suggest that the third great change, thepresent rapid growth, which began in the West between 250 and 350 years ago, may also slowdown when, or if, technology begins to yield fewer innovations. Of course, the currentknowledge revolution may continue without foreseeable end. Either way - contrary topopular belief in constant geometric growth - population can be expected in the long run toadjust to productivity. And when one takes this view, population growth is seen to representeconomic progress and human triumph rather than social failure.
人口增长
学习啦在线学习网 以往几个世纪人口的增长并不能证明人口会无限地直线向上增长直到毁灭的地步。 相反地，人口统计史料证明人口的增长完全不是稳定的。 古生态学家爱德华 ·狄维认为，在过去 100 万年间出现过 3 次重大的变动。 第一次在公元前 100 万年左右，随着在工具的制作和使用上的革新而出现人口迅速增长。 但当工具的使用所产生的新动力被充分利用以后，世界人口增长率下降并且趋于稳定。 第二次人口剧增大约始于人类开始蓄畜、垦耕的 10，000 年前。 一旦最初的生产力增长被吸收殆尽，人口的增长再次衰落。 以上两段说明，若技术革新的成果开始减少，从250 到350 年前就在西方开始出现的并且目前还在继续的人口迅速增长可能也会放慢。 当然，当前的知识革命也许会持续下去而无法预见其末来。 无论如何，与那种认为人口以几何级数持续增长的观点相反，从长远的观点来说，人口可望受到生产力的调节。 接受了这一观点，人口的增长就可以被看成是经济进步和人类胜利的标志，而不是社会衰败的标志。
初中短篇英语美文篇2
学习啦在线学习网 Police and Communities
学习啦在线学习网 Few institutions are more important to an urban community than its police, yet there are fewsubjects historians know so little about. Most of the early academic interests developed amongpolitical scientists and sociologists, who usually examined their own contemporary problemswith only a nod toward the past. Even the public seemed concerned only during crime waves,periods of blatant corruption, or after a particularly grisly episode. Party regulars andreformers generally viewed the institution from a political perspective;newspapers andmagazines-the nineteenth century's media - emphasized the vivid and spectacular.
Yet urban society has always vested a wide, indeed awesome, responsibility in its police. Notonly were they to maintain order, prevent crime, and protect life and property, but historicallythey were also to fight fires, suppress vice, assist in health services, supervise elections,direct traffic, inspect buildings, and locate truants and runaways. In addition, it was assumedthat the police were the special guardians of the citizens' liberties and the community'stranquillity. Of course, the performance never matched expectations. The record containssome success, but mostly failure; some effective leadership, but largely official incompetenceand betrayal. The notion of a professional police force in America is a creation of the twentiethcentury; not until our own time have cities begun to take the steps necessary to producemodern departments.
警察与社区
对城市社区来说，很少有比它的警察更为重要的机构了，但少有课题像历史学家们对此了解得那样少。 早期的学术兴趣是在政治科学家和社会学家中发展起来的，他们一般只研究他们自己当代的问题而对过去的问题只是偶尔带过。 甚至公众似乎也仅仅在犯罪浪潮、明目张胆的贪污或特别的恐怖事件发生时才关心。 政党的忠诚支持者和改革家们通常是从政治的前途来看待警察这个机构;而报纸和杂志-19 世纪的传播媒介-则着重活泼生动和惊人的事件。可是城市社会总是把广泛得可怕的责任交给警察。他们不仅维持秩序、防止犯罪、保护生命财产，而且在过去还要救火、镇压罪恶、协助医疗服务、监督选举、指挥交通、检查建筑物、寻找逃学学生和搜捕逃犯。 除此以外，警察还被认为是公民自由和社会稳定的特别保护者。 自然，警察的表现并不尽如人意。他们的记录中有成功者，但多数是失败的;有高效率的领导，但多半的人在职务上无能和不讲信用。 专业警察部队的概念在美国还是 20 世纪的产物;直到我们这个时代，一些城市才开始采取设立现代化部门的必要步骤。
初中短篇英语美文篇3
Plate Tectonics and Sea-floor Spreading
学习啦在线学习网 The theory of plate tectonics describes the motions of the lithosphere, the comparatively rigidouter layer of the Earth that includes all the crust and part of the underlying mantle.Thelithosphere is divided into a few dozen plates of various sizes and shapes, in general the platesare in motion with respect to one another. A mid-ocean ridge is a boundary between plateswhere new lithospheric material is injected from belows. As the plates diverge from a mid-ocean ridge they slide on a more yielding layer at the base of the lithosphere.
学习啦在线学习网 Since the size of the Earth is essentially constant, new lithosphere can be created at the mid-ocean ridges only if an equal amount of lithospheric material is consumed elsewhere. The site ofthis destruction is another kind of plate boundary: a subduction zone. There one plate divesunder the edge of another and is reincorporated into the mantle. Both kinds of plate boundaryare associated with fault systems, earthquakes and volcanism,but the kinds of geologic activityobserved at the two boundaries are quite different.
The idea of sea-floor spreading actually preceded the theory of plate tectonics. In its originalversion, in the early 1960's, it described the creation and destruction of the ocean floor, but itdid not specify rigid lithospheric plates. The hypothesis was substantiated soon afterwardby the discovery that periodic reversals of the Earth's magnetic field are recorded in theoceanic crust. As magma rises under the mid-ocean ridge, ferromagnetic minerals in themagma become magnetized in the direction of the geomagnetic field. When the magma coolsand solidifies, the direction and the polarity of the field are preserved in the magnetizedvolcanic rock. Reversals of the field give rise to a series of magnetic stripes running parallelto the axis of the rift. The oceanic crust thus serves as a magnetic tape recording of thehistory of the geomagnetic field that can be dated independently; the width of the stripesindicates the rate of the sea-floor spreading.
板块结构与海床扩展
板块结构理论描述岩石圈的运动。 岩石圈是相对坚硬的地球外层，包括全部地壳和部分地幔。 岩石圈被划分为几十个大小不同形状各异的板块，一般而言这些板块都处于相对运动之中。 一道中海脊是板块之间的边界，在那里新的岩石圈的物质从下部注入。 当板块从中海脊脱离时，它们滑向在岩石圈基部较易变形的地层上。 因为地球的大小本质上是不变的，只有同等数量的岩石圈物质在其它地方被吞没，新的岩石圈才能生成。 销毁旧岩石圈的地方形成另外一种板块边界：一块潜没的区域。 在这里，一块板块潜没到另一板块的边缘之下并结合入地幔之中。 两种板块边界均与地层系统、地震以及火山活动有关，但在两种边界处观察到的诸般地质活动却迥然不同。 海床扩展说实际上早于板块结构理论。 在20 世纪 60 年代它的理论雏形中，描述了海底的生成和毁灭，但没有详细介绍坚硬的岩石圈板块。 这个假定不久之后为发现所证实。 该发现表明地球磁场周期性的逆转被记录在海洋地壳中。 当岩浆从中海脊下涌起的时候，岩浆中的磁铁矿物质按地磁场的方向被磁化。 岩浆冷却并凝固下来后，地磁场的方向和磁极被保留在磁化了的火山岩中。 磁场的逆转形成一系列与断层轴线平行的条形磁区。 这样海洋壳就扮演了磁带的角色，记录下可以鉴定时间的地磁场的历史。 条形磁区的宽度表明了海底扩展的速度。
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