托福阅读：模拟试题及答案解析（2）

　　托福阅读原文

　　The Development of Steam Power

　　【1】By the eighteenth century, Britain wasexperiencing a severe shortage of energy. Because ofthe growth of population, most of the great forests of medieval Britain had long ago beenreplaced by fields of grain and hay. Wood was in ever-shorter supply, yet it remainedtremendously important. It served as the primary source of heat for all homes and industriesand as a basic raw material. Processed wood (charcoal) was the fuel that was mixed with ironore in the blast furnace to produce pig iron (raw iron). The iron industry’s appetite for woodwas enormous, and by 1740 the British iron industry was stagnating. Vast forests enabledRussia to become the world’s leading producer of iron, much of which was exported to Britain. But Russia’s potential for growth was limited too, and in a few decades Russia would reach thebarrier of inadequate energy that was already holding England back.

　　【2】As this early energy crisis grew worse, Britain looked toward its abundant and widelyscattered reserves of coal as an alternative to its vanishing wood. Coal was first used in Britainin the late Middle Ages as a source of heat. By 1640 most homes in London were heated withit, and it also provided heat for making beer, glass, soap, and other products. Coal was notused, however, to produce mechanical energy or to power machinery. It was there thatcoal’s potential wad enormous.

　　【3】As more coal was produced, mines were dug deeper and deeper and were constantlyfilling with water. Mechanical pumps, usually powered by hundreds of horses waling in circles atthe surface, had to be installed Such power was expensive and bothersome. In an attempt toovercome these disadvantages, Thomas Savery in 1698 and Thomas Newcomen in 1705 invented the first primitive steam engines. Both engines were extremely inefficient. Bothburned coal to produce steam, which was then used to operate a pump. However, by theearly 1770s, many of the Savery engines and hundreds of the Newcomen engines wereoperating successfully, though inefficiently, in English and Scottish mines.

　　【4】In the early 1760s, a gifted young Scot named James Watt was drawn to a critical studyof the steam engine. Watt was employed at the time by the University of Glasgow as a skilledcrafts worker making scientific instruments. In 1763: Watt was called on to repair a Newcomenengine being used in a physics course. After a series of observations, Watt saw that theNewcomen’s waste of energy could be reduced by adding a separate condenser. This splendidinvention, patented in 1769, greatly increased the efficiency of the steam engine. The steamengine of Watt and his followers was the technological advance that gave people, at least for awhile, unlimited power and allowed the invention and use of all kinds of power equipment.

　　【5】The steam engine was quickly put to use in several industries in Britain. It drained minesand made possible the production of ever more coal to feed steam engines elsewhere. Thesteam power plant began to replace waterpower in the cotton-spinning mills as well as otherindustries during the 1780s, contributing to a phenomenal rise in industrialization. TheBritish iron industry was radically transformed. The use of powerful, steam-driven bellows inblast furnaces helped iron makers switch over rapidly from limited charcoal to unlimited coke(which is made from coal) in the smelting of pig iron (the process of refining impure iron) after1770 in the 1780s, Henry Cort developed the puddling furnace, which allowed pig iron to berefined in turn with coke. Cort also developed heavy-duty, steam-powered rolling mills, whichwere capable of producing finished iron in every shape and form.

　　【6】The economic consequence of these technical innovations in steam power was a greatboom in the British iron industry. In 1740 annual British iron production was only 17:000 tons, but by 1844: with the spread of coke smelting and the impact of Cort’s inventions, it hadincreased to 3,000:000 tons. This was a truly amazing expansion. Once scarce and expensive, iron became cheap, basic, and indispensable to the economy.