托福TPO21真题解析1

　　Geothermal Energy

　　Paragraph 1: 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.

　　1. According to the processes described in paragraph 1, what is the relationship between radioactivity and the steam produced by geothermal heat?

　　○Geothermally heated steam is produced when water is exposed to radioactivity deep underground.

　　○ When water is introduced into holes drilled thousands of feet in the ground, it becomes radioactive and turns to steam.

　　○ Radioactivity heats Earth's interior rock, which in turn can heat water to the point it becomes steam.

　　○ When a reservoir of steam in subsurface rock is produced by radioactivity, it is said to be geothermally heated.

　　题型：细节题

　　定位词： relationship between radioactivity and the steam

　　解题思路： 关于定位词中的 radioactivity，只有文章开头提到其功能为为地球内部的热能提供燃料，只有选项C中提到了这一功能，所以C为正确选项。

　　重点句子翻��

　　Earth's internal heat, fueled by radioactivity, provides the energy for plate tectonics and continental drift, mountain building, and earthquakes.

　　地球内部的热量，通过辐射带动，为板块构造和大陆漂移，造山运动，地震提供了能量。

　　2. The word “practical” in the passage is closest in meaning to

　　○Usable

　　○Plentiful

　　○Economical

　　○Familiar

　　题型：词汇题

　　解题思路： “practical”是一个简单词汇，意为“实用的;实际的”，所以A项正确。

　　Paragraph 2：By far the most abundant form of geothermal energy occurs at the relatively low temperatures of 80oto 180o 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.

　　3. The word “abundant” in the passage is closest in meaning to

　　○Economical

　　○Familiar

　　○Plentiful

　　○Usable

　　题型：词汇题

　　解题思路： “relatively low temperatures” 说明在这种温度范围内地热能量的形成是最丰富的，所以C项正确。

　　4. According to paragraph 2, which of the following is true about heat reservoirs with a temperature in the range of 80° to 180° centigrade?

　　○They are under international control.

　　○They are more common than reservoirs that have a higher temperature.

　　○Few of them produce enough heat to warm large industrial spaces.

　　○They are used to generate electricity.

　　题型：细节题

　　定位词： heat reservoirs with a temperature in the range of 80° to 180° centigrade

　　解题思路：根据定位词中的数字定位到第一句话，根据意思可知在这种温度范围内地热能量的形成是最丰富的，所以B项正确。选项A、C、D的说法原文未提及。

　　重点句子翻译：

　　By far the most abundant form of geothermal energy occurs at the relatively low temperatures of 80oto 180o centigrade.

　　到目前为止，最丰富的地热能源的形式出现在相对较低的80度至180度摄氏温度。

　　Paragrapgh3：Geothermal reservoirs with temperatures above 180° centigrade are useful for generating electricity. They occur primarily in regions of recent volcanic activity as hot, dry rock; natural hot water; or natural steam. The latter two sources are limited to those few areas where surface water seeps down through underground faults or fractures to reach deep rocks heated by the recent activity of molten rock material. The world's largest supply of natural steam occurs at The Geysers, 120 kilometers north of San Francisco, California. In the 1990s enough electricity to meet about half the needs of San Francisco was being generated there. This facility was then in its third decade of production and was beginning to show signs of decline, perhaps because of over development. By the late 1990s some 70 geothermal electric-generating plants were in operation in California, Utah, Nevada, and Hawaii, generating enough power to supply about a million people. Eighteen countries now generate electricity using geothermal heat.

　　5. According to paragraph 3, what is the connection between underground faults and naturally occurring steam?

　　○ Underground faults enable the heat from molten-rock material to escape upward to regions where it can heat surface water enough to produce steam.

　　○ Underground faults are created by steam that is produced in geothermal reservoirs deep inside Earth.

　　○ Underground faults create spaces in which natural steam is sometimes trapped.

　　○ Underground faults allow surface water to reach deep rocks that are hot enough to turn it into steam.

　　题型：细节题

　　定位词： connection between underground faults and naturally occurring steam

　　解题思路：定位词 natural steam后面的一句话解释了两者的关系，地下断层让水通过、到达深处岩石，使其温度变高成为蒸汽，所以D项正确。

　　重点句子翻译：

　　The latter two sources are limited to those few areas where surface water seeps down through underground faults or fractures to reach deep rocks heated by the recent activity of molten rock material.

　　后两个能源仅限于那些地表水渗入地下断层，到达了被近期熔岩材料活动加热的深处的岩石的领域。

　　6. In paragraph 3, why does the author mention that in the 1990s The Geysers was in its third decade of production?

　　○ To provide the historical context of the geothermal production of electricity in the United States

　　○ To imply that The Geysers was the first geothermal site to be put into production in California

　　○ To help explain the signs of decline shown by The Geysers

　　○ To explain why 70 new geothermal sites were put into electricity production in the late 1990s

　　题型：修辞目的题

　　定位词： in the 1990s The Geysers was in its third decade of production

　　解题思路：这是例证目的题，答案在例子的后半句，“该设施当时在其生产的第三十年”是用来更好地说明其下降的迹象。所以c项正确。

　　重点句子翻译：

　　This facility was then in its third decade of production and was beginning to show signs of decline, perhaps because of over development.

　　该设施当时在其生产的第三十年，开始显示出下降的迹象,也许是因为过度开发。

　　Paragraph 2: By far the most abundant form of geothermal energy occurs at the relatively low temperatures of 80° 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.

　　Paragraph 3: Geothermal reservoirs with temperatures above 180" centigrade are useful for generating electricity. They occur primarily in regions of recent volcanic activity as hot, dry rock; natural hot water; or natural steam. The latter two sources are limited to those few areas where surface water seeps down through underground faults or fractures to reach deep racks heated by the recent activity of molten rock material. The world's largest supply of natural steam occurs at The Geysers, 120 kilometers north of San Francisco, California. In the 1990s enough electricity to meet about half the needs of San Francisco was being generated there. This facility was then in its third decade of production and was beginning to show signs of decline, perhaps because of overdevelopment. By the late 1990s some 70 geothermal electric-generating plants were in operation in California, Utah, Nevada, and Hawaii, generating enough power to supply about a million people. Eighteen countries now generate electricity using geothermal heat.

　　7. Which of the following can be inferred from paragraphs 2 and 3 about geothermal reservoirs?

　　O Volcanic heat is associated only with geothermal reservoirs that have a temperature over 180" centigrade.

　　O More countries produce power from geothermal reservoirs than use them for heating buildings.

　　O Most geothermal reservoirs are suitable for producing electricity.

　　O A higher geothermal reservoir temperature is needed to generate electricity than is needed to heat homes.

　　题型：推断题

　　定位词： geothermal reservoirs

　　解 题思路：A选项中的only过于绝对，找不到原文依据支持;B选项的说法也不正确，原文中并没有比较生产和使用地热能的国家的多少;C选项说法与原文矛 盾，用来发电的地热要超过180度，而最丰富的地热是在80度到180度之间。D项正确，因为 用来发电的地热要超过180度，而最丰富的地热是在80度到180度之间，可以用来取暖。

　　Paragraph 4: Extracting heat from very hot, dry rocks presents a more difficult problem: the rocks must be fractured to permit the circulation of water, and the water must be provided artificially. The rocks are fractured by water pumped down at very high pressures. Experiments are under way to develop technologies for exploiting this resource.

　　8. According to paragraph 4, extracting heat from very hot, dry rocks is difficult in part because

　　O the underground rock must be fractured before heat can be removed from it

　　O the water above the rock is under very high pressure

　　O the rock breaks apart when water is pumped into it

　　O the water circulated through the rock must be much cooler than the rock itself.

　　题型：细节题

　　定位词：extracting heat from very hot, dry rocks is difficult

　　解题思路：本段第一句出现定位词，并说明了从石头中提取热量困难的两个原因：必须在岩石裂隙允许水循环，水必须人工提供。选项A符合第一个原因的说法，为正确选项。

　　重点句子翻译：

　　Extracting heat from very hot, dry rocks presents a more difficult problem: the rocks must be fractured to permit the circulation of water, and the water must be provided artificially.

　　从非常热、干燥的岩石中提取热量提出了一个更棘手的问题：必须在岩石裂隙允许水循环，水必须人工提供。

　　Paragraph 4：Extracting heat from very hot, dry rocks presents a more difficult problem: the rocks must be fractured to permit the circulation of water, and the water must be provided artificially. The rocks are fractured by water pumped down at very high pressures. Experiments are under way to develop technologies for exploiting this resource.

　　9. The word “ exploiting” in the passage is closest in meaning to

　　O locating

　　O increasing

　　O making use of

　　O estimating the size of

　　题型：词汇题

　　解题思路： 本段前半部分说了从石头中提取热量困难的两个原因，按照正常的思考逻辑，最后一句话是说“发展技术、利用这种自然资源的实验正在开发中”。所以C项正确。

　　Paragraph 5：Like most other energy sources, geothermal energy presents some environmental problems. The surface of the ground can sink if hot groundwater is withdrawn without being replaced. In addition, water heated geothermally can contain salts and toxic materials dissolved from the hot rock. These waters present a disposal problem if they are not returned to the ground from which they were removed.

　　10. How is the problem that the surface may sink related to the problem that water heated geothermally may contain toxic materials?

　　O Both problems could be solved by returning groundwater that is removed from an underground heat reservoir back to the reservoir after heat is extracted from it.

　　O The problem of sinking is more difficult to solve than is the problem of toxic materials.

　　O Land at the surface sinks because the rock beneath the surface is weakened when salts and toxic materials are removed from it in the process of extracting geothermal energy.

　　O Both problems are caused by the fact that the hot groundwater in a heat reservoir dissolves the rock, which weakens the rock and makes the water toxic with salt.

　　题型：细节题

　　定位词： he surface may sink related to the problem that water heated geothermally may contain toxic materials

　　解题思路：根据本段结构，可知定位词中的两种现象都是地热能利用导致的环境问题，最后一句话提到了它们可能的一种解决方式，选项A是最后一句话的同义改写，为正确选项。

　　重点句子翻译：

　　These waters present a disposal problem if they are not returned to the ground from which they were removed.

　　如果不回到它们被移除的地面，这些水就会有一个处置问题。

　　Paragraph 6：The contribution of geothermal energy to the world's energy future is difficult to estimate. Geothermal energy is in a sense not renewable, because in most cases the heat would be drawn out of a reservoir much more rapidly than it would be replaced by the very slow geological processes by which heat flows through solid rock into a heat reservoir. 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. At present, we can make efficient use of only naturally occurring hot water or steam deposits. Although the potential is enormous, it is likely that in the near future geothermal energy can make important local contributions only where the resource is close to the user and the economics are favorable, as they are in California. New Zealand, and Iceland Geothermal energy probably will not make large-scale contributions to the world energy budget until well into the twenty-first century. if ever.

　　11. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

　　O Heat flows through solid rock very slowly, so it takes a very long time for geological processes to produce a reservoir of geothermal energy

　　O Geothermal energy is not renewable because heat flows very slowly through solid rock into or out of a heat reservoir

　　O The heat quickly removed from a heat reservoir is replaced so slowly by geological processes that geothermal energy is not practically speaking, renewable

　　O In most cases, heat travels into a heat reservoir so slowly that it is a much quicker process to remove the heat from a reservoir than to replace it

　　题型：句子简化题

　　解题思路： 所给句子中有一个明显的因果关系，讲的是地热能为不可再生能源的原因，选项C保留了原句主干，为正确选项。选项A和D丢失了 renewable这一重要主干;选项B中的原因不全。

　　重点句子翻译：

　　Geothermal energy is in a sense not renewable, because in most cases the heat would be drawn out of a reservoir much more rapidly than it would be replaced by the very slow geological processes by which heat flows through solid rock into a heat reservoir.

　　地热能源是在一定意义上不能再生的，因为在大多数情况下，热量被抽出一个水库速度远远超过它被取代的速度，那将是非常缓慢的地质过程，其中热量通过坚硬的岩石流进一热储层。

　　Paragraph 6：The contribution of geothermal energy to the world's energy future is difficult to estimate Geothermal energy is in a sense not renewable, because in most cases the heat would be drawn out of a reservoir much more rapidly than it would be replaced by the very slow geological processes by which heat flows through solid rock into a heat reservoir. 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. At present, we can make efficient use of only naturally occurring hot water or steam deposits. Although the potential is enormous, it is likely that in the near future geothermal energy can make important local contributions only where the resource is close to the user and the economics are favorable, as they are in California. New Zealand, and Iceland. Geothermal energy probably will not make large-scale contributions to the world energy budget until well into the twenty-first century, if ever.

　　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.

　　题型：句子插入题

　　解题思路： 所给句子中 In either case(在这两种情况下)，说明这句话前面有两种不同的情况，通过阅读，第二个方框前的 usually和 less typically提示了两种不同情况下水的状态，所以应该把这句话插入第二个方框。

　　14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

　　Heat reservoirs in the form of hot rock far beneath Earth’s surface are a potential source of usable geothermal energy.

　　●

　　●

　　●

　　Answer choices

　　A. Heat reservoir with a temperature from 80o to 180° centigrade can be used, as in France and Iceland, to heat buildings.

　　B.Most heat reservoirs with a temperature above 180° centigrade cannot be used for energy because they are usually too close to recent volcanic activity.

　　C.Experiments are under way to determine if geothermally heated waters could be used as a source of certain minerals that have been dissolved out of hot rocks deep within Earth.

　　D.A number of countries now use geothermal reservoirs that contain water or steam above 180° centigrade to generate electricity

　　E. The sinking of land above heat reservoirs and other environmental problem arise when water is pumped into a heat reservoir under high pressure

　　F.A number of issues, including how to extract heat from reservoirs that do not have a natural supply of water, will significantly limit the use of geothermal energy for the foreseeable future.

　　题型：总结题

　　解题思路：选项B与原文矛盾，180度以上的地热能可以用来发电;选项C原文未提及;选项E也是错误的，地表沉降的原因是地下水的流失。选项A是第二段的主要内容;选项D是第三段的主要内容;选项F是第四、五、六段的主要内容。

　　本文核心词汇：

　　artificially: adv. 人工地

　　tectonics: n. 构造学

　　harness: v. 治理;利用

　　reservoir: n. 水库;储藏

　　residential: adj. 住宅的

　　derive: v. 源于…

　　facility: n. 设施;能力

　　withdraw: v. 取回;撤出

　　dissolve: v. 溶解;消除

　　enormous: adj. 巨大的，极大的，庞大的