Since about 1800,
near the beginning of the Industrial Revolution, coal, petroleum, and gas have
been used at a rapidly increasing rate. The supply of these {{U}}(51)
{{/U}} is limited, and electric power is very scarce in many places. Some
scientists believe solar energy is the only {{U}}(52) {{/U}} which can
meet the world's enormous {{U}}(53) {{/U}} for power. Great progress had
been made in harnessing the sun. Not {{U}}(54) {{/U}} is the sun now
used in cooking, but it also supplies power for {{U}}(55) {{/U}} things
as beacon lights for ships and airplanes. It operates telephone lines, portable
radios, electric clocks, hearing aids, and {{U}}(56) {{/U}}
communication satellites. Some homes and office buildings in the United States
are now being {{U}}(57) {{/U}} with solar energy. The
three most significant types of solar equipment so {{U}}(58) {{/U}} are
the furnace, the still, and the cell. Solar furnaces heat water or air,
{{U}}(59) {{/U}} is then circulated through a building to make it
comfortable. Solar stills are {{U}}(60) {{/U}} important because they
can provide {{U}}(61) {{/U}} water at a relatively cheap rate. Salt can
be easily removed from sea water with a solar still. The most
highly developed is the solar cell. Some cells are so {{U}}(62) {{/U}}
that they can turn 16 percent of the energy they received from the sun into
electric energy. One of the cell's biggest advantages is {{U}}(63)
{{/U}} it can be made either small enough to carry {{U}}(64) {{/U}}
large enough to produce a current that can run an automobile. Besides, it has a
very long life. It is still too expensive for the average consumer. But when
ways are {{U}}(65) {{/U}} to produce it more cheaply, we can expect its
use to be widespread.
【答案解析】本题需要选出一个动词与ways搭配,ways表示方法,方法只可以发现而不可以发明,所以应选discover,此处的基本结构为discover ways to do sth.意为“发现做……的方法”。disclose意为“某物显露,公开某事,透露某事”;reveal意为“泄露,透露,揭露(事实等)”。