Constant variations in the amount of sunlight available on Earth at any given location make energy storage a necessary design fe

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问题     Constant variations in the amount of sunlight available on Earth at any given location make energy storage a necessary design feature of terrestrial solar-energy systems. For systems transforming solar to thermal energy, the thermal energy may be stored in matter as either latent heat or sensible heat. Latent heat is absorbed or released whenever matter changes phase, as when matter changes from liquid to gas, for example, or from gas to liquid. Large heat capacities are associated with certain materials, like salts, but in any substance this storage is available only at the unique fixed temperature at which the particular phase transition occurs in that substance. Moreover, materials that have transitions at the temperatures that terrestrial solar-energy systems are likely to encounter are usually destructively corrosive at those temperatures. The storage of sensible heat, on the other hand, allows flexibility as to temperature, in addition, safe substances like water and most rocks have large sensible heat capacities.
The primary purpose of the passage is to discuss which of the following?

选项 A、Reasons for the necessity for developing solar-energy systems
B、Different ways of storing solar energy as heat
C、New designs for devices that collect solar energy
D、Procedures for transferring thermal energy between materials
E、Differences between capacities of solids and liquids to store sensible heat

答案B

解析 本题属于主旨题,而本文是总分结构,因此正确答案只要同义改写本文主旨句即可,故选项B正确。different ways对应的是潜热和显热。A项文中未提及。C项文中未提及。D项属于细节。E项文中未提及。
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本试题收录于: GRE VERBAL题库GRE分类
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