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Transportation is the movement or conveying of persons and goods from one location to anot

her. As human beings, from ancient times to the 21st century, sought to make their transport facilities more efficient, they have always endeavored to move people and property with the least expenditure of time, effort and cost. Improved transportation had helped make possible progress toward better living, the modern systems of manufacturing and commerce, and the complex, interdependent urban economy present in much of the world today.

Primitive human beings supplemented their own carrying of goods and possessions by starting to domesticate animals — training them to bear small loads and pull crude sleds. The invention of the wheel, probably in western Asia, was a great step forward in transport. As the wheel was perfected, crude carts and wagons began to appear in the Tigris-Euphrates valley about 3500 BC, and later in Crete, Egypt, and China. Wheeled vehicles could not use the narrow paths and trails used by pack animals, and early roads were soon being built by the Assyrians and the Persians.

The greatest improvements in transportation have appeared in the last two centuries, a period during which the industrial Revolution has vastly changed the economic life of the entire world. Crude railways — horse-drawn wagons with wooden wheels and rails — had been used in English and European mines during the 17th century. Although it first appeared in England, the railroad had its most dramatic growth in the United States. By 1840 more than 4800 km of railroads were already operating in the eastern states, a figure 40 percent greater than the total railroad mileage of Europe. Since World War I, however, the U.S. railroads have been in a decline, due partly to the rapid development of private automobiles, trucks, buses, pipelines, and airlines.

The first new mode of transportation to challenge the railroad was the motor vehicle, which was made possible by the invention, in the 1860s and 70s, of the internal combustion engine. The automobile found its greatest popularity in the United States, where the first "horseless carriages" appeared in the 1890s. Two hundred million motor vehicles had been produced in the nation within 70 years of their first appearance. The automobile thus became in many ways as important to the 20th century as the railroads had been to the 19th.

During the same period intercity buses took over a large portion of commercial passenger travel, and trucks began carrying a great deal of the nation's freight.

Although the emphasis on fuel conservation waned in "the 1980s, few doubt that the issue will emerge again when oil scarcities loom, as they did in the 1970s. Future possibilities include automobiles with far greater fuel efficiency and improved mass-transit systems. Both will occur not only in response to oil-supply disruption, but also as an answer to increasing demands for cleaner air. Improvements in mass transit offer the most promise for the future. Amtrak's 1993 introduction of the Swedish high-speed "tilting train" should cut travel time between some East Coast cities by almost half, once tracks are entirely electrified.

From the first paragraph, it can be inferred that transport exerts a great influence on all the following EXCEPT______.

A.economic development

B.living conditions

C.industrial production

D.political rights

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更多“Transportation is the movement or conveying of persons and goods from one location to anot”相关的问题

第1题

机械式停车设备驱动装置必须设有()制动器,当电机或控制器不接电时,应能起到制动作用。

A.常闭

B.带式

C.常开

D.盘式

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第2题

机械式停车设备主机必须设有制动系统,制动系统应采用常开式制动器。()

A. 不确

B. 错误

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第3题

《机械式停车设备通用安全要求》(GB17907—2010)规定,机械式停车设备主机必须设有制动系统,制动系统应采用常闭式制动器,对控制升降运动的制动器,其制动力矩不应小于()倍额定载荷的制动力矩。

A.1.2

B.1.5

C.1.7

D.1.8

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第4题

机械式停车设备的制动系统应采用()制动器。A.常开式B.常闭式C.综合式

机械式停车设备的制动系统应采用()制动器。

A.常开式

B.常闭式

C.综合式

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第5题

常用式制动器在制动装置处于静态时应是()状态。A、常闭B、常开

常用式制动器在制动装置处于静态时应是()状态。

A、常闭

B、常开

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第6题

机械式停车设备常闭制动器的额定制动力矩应不小于()倍额定载荷产生的力矩。A.1.1B.1.2C.1.5D.2

机械式停车设备常闭制动器的额定制动力矩应不小于()倍额定载荷产生的力矩。

A.1.1

B.1.2

C.1.5

D.2

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第7题

机械式停车设备的制动器应采取常开式制动器。
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第8题

机械式停车设备的制动器对制动摩擦片的磨损应有()能力。A.控制B.补偿C.测试D.恢复

机械式停车设备的制动器对制动摩擦片的磨损应有()能力。

A.控制

B.补偿

C.测试

D.恢复

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第9题

曳引驱动电梯机电式制动器的要求____。

A.必须是“常闭式”制动器

B.不允许使用带式制动器

C.正常停车时,制动器“零速”抱闸制动

D.全部选项

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