单项选择题
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Text If the sun has enough (26) to warm and light the whole earth, it must have enough power to do other things, (27) . Can we use the sun’s (28) energy to supply electricity, or at least to perform the function which electricity or other types of power usually perform The answer is (29) . For example, people have for many years been using the (30) heat of the sun to cook by solar (31) which have been built with several incurred (32) reflecting the sun and focusing the heat on the cooking element. This (33) can be used like a gas or electric stove; it is more expensive to make but it doesn’t need any (34) and so costs (35) to use. Another (36) of using solar energy is in house heating. The (37) of energy we use most is electricity, and every day more is (38) . But electricity has to be made too, and to make it huge quantities of fuel is required -- oil, coal, gas and nowadays even uranium. The question which (39) everyone today is: how long will these fuels (40) Nobody knows it for sure, (41) most experts think it will soon be difficult to obtain sufficient electricity from these sources. It is possible that the sun can make a(n) (42) here, too. Solar power has already been used to produce (43) heat. In Southern France a solar furnace has been built, (44) temperatures reach more than 3 000 centigrade. This furnace is not only used for experiment (45) , but could be used to produce steam for a power station. |