12. In paragraph 6, the author implies that in California, Hawaii, the Philippines, Japan, Mexico, and the rift valleys of Africa the potential size of the geothermal resource is so large that

　　O it might be economically worth developing these sites even though geothermal energy is not renewable

　　O these sites will be the first geothermal energy sites to be developed with new technology

　　O these sites are likely to make a large-scale contribution to the world energy budget in the twenty-first century

　　O it does not matter whether they have naturally occurring deposits of hot water or steam

　　题型：推断题

　　定 位词： in California, Hawaii, the Philippines, Japan, Mexico, and the rift valleys of Africa the potential size of the geothermal resource is so large that

　　解题思路：根据定位词定位到原文“its future will depend on the economics of production”, 选项A是这一观点的一种可能性，为正确选项。

　　重点句子翻译：

However, in many places (for example, California, Hawaii, the Philippines Japan, Mexico, the rift valleys of Africa) the resource is potentially so large that its future will depend on the economics of production.

　　然而，在很多地方（例如加利福尼亚，夏威夷，日本，菲律宾，墨西哥，非洲的裂谷）的资源是如此之大，其潜在的未来将取决于生产的经济性。

　　Earth's internal heat, fueled by radioactivity, provides the energy for plate tectonics and continental drift, mountain building, and earthquakes. It can also be harnessed to drive electric generators and heat homes. Geothermal energy becomes available in a practical form when underground heat is transferred by water that is heated as it passes through a subsurface region of hot rocks (a heat reservoir) that may be hundreds or thousands of feet deep. ■The water is usually "naturally occurring groundwater that seeps down along fractures in the rock; less typically, the water is artificially introduced by being pumped down from the surface. ■ The water is brought to the surface, as a liquid or steam, through holes drilled for the purpose. ■

　　By far the most abundant form of geothermal energy occurs at the relatively low temperatures of 80o to 180° centigrade. ■ Water circulated through heat reservoirs in this temperature range is able to extract enough heat to warm residential, commercial, and industrial spaces. More than 20,000 apartments in France are now heated by warm underground water drawn from a heat reservoir in a geologic structure near Paris called the Paris Basin. Iceland sits on a volcanic structure known as the Mid-Atlantic Ridge. Reykjavik, the capital of Iceland, is entirely heated by geothermal energy derived from volcanic heat.

　　13. Look at the four squares [■] that indicate where the following sentence could be added to the passage.

　　In either case, the heated water will usually be under considerable pressure, and so may have a temperature that is well above its sea-level boiling point of 100° centigrade.

　　Where would the sentence best fit? Click on a square to add the sentence to the passage.