科技英语阅读4The invention of the incandescent (白炽的) light bulb by

科技英语阅读4
The invention of the incandescent (白炽的) light bulb by Thomas Edison in 1879 created a demand for a cheap,readily available (可利用的) fuel with which to generate large amounts of electric power.Coal seemed to fit the bill,and it fueled (供以燃料) the earliest power stations (which were set up at the end of the nineteenth century by Edison himself).As more power plants (发电厂) were constructed throughout the country,the reliance (依靠) on coal increased.Since the First World War,coal-fired power plants have accounted for about half of the electricity produced in the United States each year.In 1986 such plants had a combined capacity (产量) of 289 000 megawatts and consumed (消耗) 83 percent of the nearly 900 million tons of coal mined in the country that year.Given (考虑到) the uncertainty in the future growth of nuclear power and in the supply of oil and natural gas,coal-fired power plants could well provide up to 70 percent of the electric power in the United States by the end of the century.
Yet,in spite of the face that coal has long been a source of electricity and may remain one for many years (coal represents about 80 percent of the United States fossil-fuel reserves,it has actually never been the most desirable fossil fuel for power plants.Coal contains less energy per unit of weight than natural gas or oil; it is difficult to transport,and it is associated with a host of environmental issues among them acid rain.Since the late 1960s problems of emission (散发) control and waste disposal have sharply reduced the appeal of coal-fired power plants.The cost of ameliorating (改进) these environmental problems,along with the rising cost of building a facility (设备) as large and complex as a coal-fired power plant,has also made such plants less attractive from a purely economic perspective (观点).
Changes in the technological base of coal-fired power plants could restore (恢复) their attractiveness,however.Whereas some of these changes are evolutionary (进化的) and are intended mainly to increase the productivity of existing plants,completely new technologies for burning coal cleanly are also being developed.
31.What is the main idea of the passage?
a.Coal-fired plants are an important source of electricity in the United States and are likely to remain so.
b.Generating electricity from coal is comparatively recent in the United States.
c.Coal is a more economical fuel than either oil or nuclear power.
d.Coal is a safer and more dependable fossil fuel than oil or gas.
32.Edison’s electric light bulb is mentioned in the passage because it .
a.replaced gas as a light source
b.increased the need for electrical power
c.was safer than any other method of lighting
d.could work only with electricity generated from coal
33.It can be inferred from the passage that coal became the principal source (主要的来源) of electricity in the United States because it .
a.required no complicated machinery (复杂的机械)
b.was comparatively (相对的)plentiful and inexpensive
c.was easy to transport
d.burned efficiently
34.In the author’s opinion,the importance of coal-generated electricity could increase in the future for which of the following reasons?
a.The possible substitutes (代替物) are too dangerous.
b.The cost of changing to other fuels is uncertain
c.The future availability (可用性) of other fuels is uncertain.
d.Other fuels present too manyenvironmental problems.
35.According to the passage,which of the following is one of the goals of the new technology in coal-fired plants?
a.To adapt (使适应) ,the plants to other kinds of fuel.
b.To reduce the cost of building more plants.
c.To lengthen the lives of plants already in use.
d.To make the plants already in use more productive.