第一篇： EARTH AGE
第一篇是讲的早期科学家们估计地球寿命。
首先说人们很早就在预估地球寿命了；之后一段讲的近代一位科学家采用生物一代代进化速度的方式预估了三叠纪的长度，但基于的假设是进化速率基本相同，其估计已经有一定准确度了。后来讲科学家利用这种方式预估地球寿命，其弱点是有部分化石找不到而且更基本的错误是地球在生物诞生之前那段时间无法估计。（这里有插空题）之后讲了科学家用其他方式预估，有种是采用测算地壳沉积岩石厚度的方法，但问题是没有考虑板块运动以及腐蚀。另一种是计算海水盐度发，理想地认为一开始地球海洋是淡水，不断地填充盐才有了现在这样子，但这也忽略了盐分与海底大陆架之间的复杂作用以及其他（这里会考题问科学家忽略了什么）。但作者对于科学家基于盐度推出的几千万年的寿命还是给予肯定的。因为这已经验证了地球寿命远比原先预计的几百万年要多得多。而且也有一批科学家从其他领域验证了这个结果。
The age of the Earth is 4.54 ± 0.05 billion years.This age is based on evidence from radiometric age dating of meteorite material and is consistent with the ages of the oldest-known terrestrial and lunarsamples. Following the scientific revolution and the development of radiometric age dating, measurements of lead in uranium-rich minerals showed that some were in excess of a billion years old.
Because the exact accretion time of Earth is not yet known, and the predictions from different accretion models range from a few millions up to about 100 million years, the exact age of Earth is difficult to determine. It is also difficult to determine the exact age of the oldest rocks on Earth, exposed at the surface, as they are aggregates of minerals of possibly different ages.
【岩层研究法】Studies of strata, the layering of rocks and earth, gave naturalists an appreciation that Earth may have been through many changes during its existence. These layers often contained fossilized remains of unknown creatures, leading some to interpret a progression of organisms from layer to layer.
In the 1790s, the British naturalist William Smith hypothesized that if two layers of rock at widely differing locations contained similar fossils, then it was very plausible that the layers were the same age. William Smith's nephew and student, John Phillips, later calculated by such means that Earth was about 96 million years old.
The naturalist Mikhail Lomonosov, regarded as the founder of Russian science, suggested in the mid-18th century that Earth had been created separately from the rest of the universe, several hundred thousand years before. Lomonosov's ideas were mostly speculative, but in 1779, the French naturalist the Comte du Buffon tried to obtain a value for the age of Earth using an experiment: He created a small globe that resembled Earth in composition and then measured its rate of cooling. This led him to estimate that Earth was about 75,000 years old
In 1862, the physicist William Thomson （who later became Lord Kelvin） of Glasgow published calculations that fixed the age of Earth at between 20 million and 400 million years. He assumed that Earth had formed as a completely molten object, and determined the amount of time it would take for the near-surface to cool to its present temperature. His calculations did not account for heat produced via radioactive decay （a process then unknown to science） or convection inside the Earth, which allows more heat to escape from the interior to warm rocks near the surface.
【生物进化方法】Geologists had trouble accepting such a short age for Earth. Biologists could accept that Earth might have a finite age, but even 100 million years seemed much too short to be plausible. Charles Darwin, who had studied Lyell's work, had proposed his theory of the evolution of organisms by natural selection, a process whose combination of random heritable variation and cumulative selection implies great expanses of time. （Geneticists have subsequently measured the rate of genetic divergence of species, using the molecular clock, to date the last universal ancestor of all living organisms no later than 3.5 to 3.8 billion years ago）。
In a lecture in 1869, Darwin's great advocate, Thomas H. Huxley, attacked Thomson's calculations, suggesting they appeared precise in themselves but were based on faulty assumptions. The German physicist Hermann von Helmholtz （in 1856） and the Canadian astronomer Simon Newcomb （in 1892） contributed their own calculations of 22 and 18 million years respectively to the debate: they independently calculated the amount of time it would take for the Sun to condense down to its current diameter and brightness from the nebula of gas and dust from which it was born. Their values were consistent with Thomson's calculations. However, they assumed that the Sun was only glowing from the heat of its gravitational contraction. The process of solar nuclear fusion was not yet known to science.
Other scientists backed up Thomson's figures as well. Charles Darwin's son, the astronomer George H. Darwin of the University of Cambridge, proposed that Earth and Moon had broken apart in their early days when they were both molten. He calculated the amount of time it would have taken for tidal friction to give Earth its current 24-hour day. His value of 56 million years added additional evidence that Thomson was on the right track.
【Radiometric dating同位素年龄测定法】Rockminerals naturally contain certain elements and not others. By the process of radioactive decay of radioactive isotopes occurring in a rock, exotic elements can be introduced over time. By measuring the concentration of the stable end product of the decay, coupled with knowledge of the half life and initial concentration of the decaying element, the age of the rock can be calculated. Typical radioactive end products are argon from potassium-40 and lead from uranium and thorium decay. If the rock becomes molten, as happens in Earth's mantle, such nonradioactive end products typically escape or are redistributed.Thus the age of the oldest terrestrial rock gives a minimum for the age of Earth assuming that a rock cannot have been in existence for longer than Earth itself.Modern radiometric dating
Radiometric dating continues to be the predominant way scientists date geologic timescales. Techniques for radioactive dating have been tested and fine-tuned for the past 50+ years. Forty or so different dating techniques have been utilized to date, working on a wide variety of materials. Dates for the same sample using these different techniques are in very close agreement on the age of the material.
Possible contamination problems do exist, but they have been studied and dealt with by careful investigation, leading to sample preparation procedures being minimized to limit the chance of contamination. Hundreds to thousands of measurements are done daily with excellent precision and accurate results. Even so, research continues to refine and improve radiometric dating to this day
Source:http://en.wikipedia.org/wiki/Age_of_the_Earth
第二篇： GERMAN RAILWAY
第二篇讲的是近代德国基于铁路工业的发展。
这篇结构为很简洁的三段。第一段总起说了下德国发展铁路后带动了一系列的发展进步。第二段细说了下铁路引领了什么进步，主要是铁、煤以及其他诸如化工产业之类的发展。然后作者列举了一个现象，通过铁路带动化工产业这个例子来阐述。（这里考作者的阐述方法）之后还强调了下铁路带动了一个P城市的兴旺，这个城市通过兴建各种配套设施啥的，体现了铁路给城市带来的翻天覆地的变化。第三段主要还是围绕P展开说了下，说由于铁路使得市场扩大了之类的。之后说了铁路还帮助人们能够在更大范围找工作以及周边产业给了更多的人就业机会。（这里有双选题）最后还说铁路打通了德国东西的连接，（运河是南北的）标志着德国工业的振兴blabla。
German Railways.
As far as railway development is concerned, no corner of the world is making more rapid progress than Germany. A recent survey issued by the German railway authorities states that, during 1927, the German railways handled 1,909,000,000 passengers and 489,000,000 tons of merchandise. Steam locomotives number 24,575 and electric locomotives 316. The German railways operate some 62,940 passenger carriages, and the stock of goods wagons totals 674,318. As a result of a consistent effort at standardization, the number of types of locomotives in service on the German lines has been reduced from 250 in 1920 to 40 at the present time. Despite this standardization, the door is being left open to experiment, and, at the moment, attention is being devoted to the development of high pressure locomotives, some of these experimental machines having steam pressures as high as 880lbs. per square inch.
German Railway history began with the opening of the steam-hauled Bavarian Ludwig Railway between Nuremberg and Fürth on 7 December 1835. This had been preceded by the opening of the horse-hauled Prince William Railway on 20 September 1831. The first long distance railway was the Leipzig-Dresden railway, completed on 7 April 1839.
German unification in 1871 stimulated consolidation, nationalization into state-owned companies, and further rapid growth. Unlike the situation in France, the goal was support of industrialization, and so heavy lines crisscrossed the Ruhr and other industrial districts, and provided good connections to the major ports of Hamburg and Bremen. By 1880, Germany had 9,400 locomotives pulling 43,000 passengers and 30,000 tons of freight, and forged ahead of France
Source：http://nzetc.victoria.ac.nz/tm/scholarly/tei-Gov03_11Rail-t1-body-d7-d2-d6.html
Social and economic benefits
【P的兴旺】Prussia nationalized its railways in an effort both to lower rates on freight service and to equalize those rates among shippers. Instead of lowering rates as far as possible, the government ran the railways as a profitmaking endeavor, and the railway profits became a major source of revenue for the state. The nationalization of the railways slowed the economic development of Prussia because the state favoured the relatively backward agricultural areas in its railway building. Moreover, the railway surpluses substituted for the development of an adequate tax system.
In order to enable the free exchange of goods wagons between the different state railway administrations, the German State Railway Wagon Association （DeutscherStaatsbahnwagenverband or DSV） was formed in 1909. The standard wagons that resulted are often referred to as 'DSV wagons'.
The standardisation of goods wagons under the German State Railway Wagon Association, that had produced the Verbandsbauart （'Association design'） wagons, continued as new designs using interchangeable components were introduced from about 1927. These were the Austauschbauart （'interchangeable design'） wagons. The 1930s saw the introduction of welded construction and solid wheels replacing spoked wheels on new goods wagons. As the Second World War loomed, production was geared towards the war effort. The focus was on fewer types but greater numbers of so-called Kriegsbauart or wartime designs for the transportation of large quantities of tanks, vehicles, troops and supplies.
【德国铁路对工业影响】During the Second World War, austere versions of the standard locomotives were produced to speed up construction times and minimise the use of imported materials. These were the so-called war locomotives （Kriegslokomotiven and ?bergangskriegslokomotiven）。 Absent a good highway network and trucks, the Germans relied heavily on the railways, supplemented by slower river and canal transport for bulk goods. The rail yards were the main targets of the "transportation strategy" of the British and American strategic bombing campaign of 1944-45, and resulted in massive destruction of the system.
