历年gre写作真题及答案，GRE阅读解析Passage43
历年gre写作真题及答案，GRE阅读解析Passage43 E. differences between capacities of solids and liquids to store sensible heatD. procedures for transferring thermal energy between materialsA. reasons for the necessity for developing solar-energy systemsB. different ways of storing solar energy as heatC. new designs for devices that collect solar energy
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.
1. The primary purpose of the passage is to discuss which of the following?
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
Consider each of the choices separately and select all that apply.
2. According to the passage solar-energy systems located on Earth must store energy for which of the following reasons?
A. At any given location on Earth the amount of sunlight available frequently changes.
B. The operation of such systems depends on devices that require a power source other than solar energy
C. Demand for the energy produced by such systems varies in unpredictable ways
答案：A
Consider each of the choices separately and select all that apply.
3.The author suggests that which of the following constitutes a potential disadvantage of using latent heat for energy storage?
A. The circumstances under which phase transitions occur would limit the versatility of latent heat as a storage method.
B. The supply of substances that possess the properties that are needed in a medium for latent heat storage is dwindling.
C. The properties that are needed in a medium for latent heat storage are found in substances that have other undesirable properties.
答案：AC
解析见下。
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.
第1句：地球上任何特定位置上可获得的太阳光的量不断变化，使得储能成为地面太阳能系统的必要设计特征。
地球上的任意一个地方，在该地上，能获得的太阳能有什么特征？
特征是，同一个地方，能接收到的太阳光的量⬆是不断变化的，不稳定的。也就是有时候多，有时候少。这很容易理解，因为显然白天光多，晚上光少到没有；晴天光多，阴天光少；夏天光多，冬天光少。
光的量不断变化这种特点，使得人们设计的太阳能系统必须满足什么条件才能用？
必须能够储能。
因为使用者不可能只在阳光灿烂的时候才使用太阳能，而是每时每刻都可能需要使用。所以陆地太阳能系统必须能够在阳光充足的时候把光能储存起来，以备阳光不足的时候使用。
那，怎么储能呢？
For systems transforming solar to thermal energy the thermal energy may be stored in matter as either latent heat or sensible heat.
第2句：对于将太阳能转化为热能的系统，热能可能以潜热或显热的形式存储在物质中。
（在太阳能系统中）太阳能是转化为热能储存的。热量必须储存在物质中，可以有两种储存的形式。
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.
第3句：当物质发生相变时，例如物质从液体变成气体，或者从气体变成液体时，潜热被吸收或释放。
潜热的储能形式：利用物质的状态变化——物质的状态变化能够储存或者释放能量。
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.
第4句：大的热容量与某些材料（如盐）有关，但是在任何物质中，只有在该物质发生特定相变的唯一固定温度下才可以使用这种储存。
潜热的限制：1、只有某些物质才具有大热容量，也就是其状态变化能储存大量热量。
2、即使有些物质热容量很大，但使用潜热的一个问题是，物质只会在到达特定温度才会才会发生状态变化（相变），这时候才可能储热。条件较为苛刻。
Moreover materials that have transitions at the temperatures that terrestrial solar-energy systems are likely to encounter are usually destructively corrosive at those temperatures.
第5句：此外，在地面太阳能系统可能遇到的温度下具有转变的材料通常在这些温度下具有破坏性的腐蚀性。
潜热还有限制3：在地面太阳能系统可能遇到的温度范围中，能够发生相变的材料，通常也处于具有腐蚀性的状态。
潜台词是，潜热的限制太多，利用潜热作为太阳能储能方式不太现实。
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.
第6句：另一方面，显热的储存允许温度的灵活性，此外，安全的物质如水和大多数岩石具有大的显热容量。
另一种储热方式：显热。
这种方式允许温度的灵活性：并非只会在到达特定温度才会才能储热，这是相比潜热的优点1。
安全的物质如水和大多数岩石具有大的显热容量：在储能大这一点上，显热和潜热优势相当，都能找到具有大容量的物质；在安全这一点上，显热胜过潜热。具有大容量又安全（无腐蚀性）的物质有很多，比如水和大多数岩石。
1. The primary purpose of the passage is to discuss which of the following?
这篇文章的主要目的是讨论下列哪一项？
A. reasons for the necessity for developing solar-energy systems
A.开发太阳能系统的必要性的原因
没讨论过必要不必要。错。
B. different ways of storing solar energy as heat
B.将太阳能储存为热量的不同方式
就是文章讨论的显热和潜热。对。
C. new designs for devices that collect solar energy
C.收集太阳能设备的新设计
咦？没说新设计呀。错。
D. procedures for transferring thermal energy between materials
D.材料之间传递热能的程序
文章根本没讨论过材料【之间】是如何传递热能的。错。
E. differences between capacities of solids and liquids to store sensible heat
E.固体和液体储存显热的能力之间的差异
文章并没有指出.固体和液体之间储存显热的能力有何差异。错。
Consider each of the choices separately and select all that apply.
分别考虑每个选项并选择所有适用的选项。
2. According to the passage solar-energy systems located on Earth must store energy for which of the following reasons?
根据文章，位于地球上的太阳能系统必须储存能量的原因是？
A. At any given location on Earth the amount of sunlight available frequently changes.
A.在地球上的任何一个地方，可用的日光量经常变化。
就是原文的意思，正因为光的量不固定，所以要在光线充足的时候储存能量。A对。
B. The operation of such systems depends on devices that require a power source other than solar energy
B.此类系统的运行取决于需要太阳能以外的能源设备
完全没这么说过。B错。
C. Demand for the energy produced by such systems varies in unpredictable ways
C.对这种系统产生的能源的需求以不可预知的方式变化
文章完全没说过需求会变化。只说了太阳光的量本身会变化，也就是供给会变化。C错。
第三题解析略。需要请留言。
