The full influence of mechanization began shortly after 1850, when a variety of machines came rapidly into use. The introduction of these machines frequently created rebellions by workers who were fearful that the machines would rob them of their work. Patrick Bell, in Scoffland, and Cyrus McCormick, in United States, produced threshing machines. Ingenious improvements were made in plows to compensate for different soil types. Stream power came into use in 1860s on large farms. Hay rakes, hay-loaders, and various special harvesting machines were produced. Milking machines appeared. The internal-combustion engine run by gasoline became the chief power source for the farm. In time, the number of certain farm machines that came into use skyrocketed and changed the nature of fanning. Between 1940 and 1960, for example, 12 million horses and mules gave way to 5 million tractors. Tractors offer many features that are attractive to farmers. There are, for example, numerous attachments: cultivators that can penetrate the soil to varying depths, rotary hoes that chop needs; spray devices that can spray pesticides in bands 100 feet across, and many others. A piece of equipment has now been invented or adapted for virtually every laborious hand or animal operation on the farm. In the United States, for example, cotton, tobacco, hay, and grain are planted, treated for pests and diseases, fertilized, cultivated and harvested by machine. Large devices shake fruit and nut from trees; grain and blend feed, and dry grain and hay. Equipment is now available to put just the right amount of fertilizer in just the right place, to spray and exact row width, and to count out, space, and plant just the right number of seeds for a row. Mechanization is not used in agriculture in many parts of Latin America, Africa. Agriculture innovation is accepted fastest where agriculture is already profitable and progressive. Some mechanization has reached the level of plantation agriculture in parts of the tropics, but even today much of that land us laboriously worked by people leading draft animals pulling primitive plows. The problems of mechanization in some areas are not only cultural in nature. For examples, tropical soils and crops differ markedly from those in temperate areas that the machines are designed for, so adaptations have to be made. But the greatest obstacle to mechanization is the fear in underdeveloped countries that the workers who are displaced by machines would not find work elsewhere. Introducing mechanization into such areas requires careful planning.
单选题
The first paragraph uses several examples to convey the ideas that ______.
【正确答案】
B
【答案解析】解析：本题考查归纳文章某一部分大意的能力。答案选项意为："内燃机(internal-combustion machine)作为主要能源在农业上的应用产生的巨大影响"。工业革命于19世纪60年代开始于英国，其主要推动力和标志是内燃机的发明，表现形式是逐渐的机械化，农业也不例外。文章第一段指出 1850年后不久，机械化的影响逐渐展开，各种机器迅速投入使用，引起了人们的抵抗，因为他们惧怕会被机器代替，失去工作 (rob them of their work)。下文列举了犁、干草耙、装草机、收割机、挤奶机等几种重要机械农具的发明，用以说明第一段第一句和最后一句所概括的内容。最后一句可译为："以汽油作燃料的内燃机成为农具的主要动力(power source)"。
单选题
From the second paragraph, we know that ______.