21. The primary purpose of the passage is to
alert readers to the existence of HDRs as an available energy source
document the challengers that have been surmounted in the effort to recover energy from HDRs
warn the users of coal and oil that HDRs are not an economically feasible alternative
encourage the use of new techniques for the recovery of energy from underground hot water and steam
urge consumers to demand quicker development of HDR resources for the production of energy
22. The passage would be most likely to appear in a
petrological research report focused on the history of temperature-depth records in the United States
congressional report urging the conservation of oil and natural gas reserves in the United States
technical journal article concerned with the recoverability of newly identified energy sources
consumer report describing the extent and accessibility of remaining coal resources
pamphlet designed to introduce homeowners to the advantages of HDR space-heating systems
23. According the passage, an average geothermal gradient of 22℃ per kilometer of depth can be used to
balance the economics of HDR energy retrieval against that of underground hot water or steam recovery systems
【gre阅读练习每日一篇(一)】相关文章:
最新
2016-03-01
2016-03-01
2016-03-01
2016-03-01
2016-03-01
2016-03-01