Section C

　　Passage One

　　Questions 46 to 50 are based on the following passage.

　　California has been facing a drought for many years now， with certain areas even having to pump freshwater hundreds of miles to their distribution system. The problem is growing as the population of the state continues to expand. 46.New research has found deep water reserves under the state which could help solve their drought crisis. Previous drilling of wells could only reach depths of 1，000 feet， 47.but due to new pumping practices， water deeper than this can now be extracted （抽取）. The team at Stanford investigated the aquifers（地下蓄水层）below this depth and found that reserves may be triple what was previously thought.

　　It is profitable to drill to depths more than 1，000 feet for oil and gas extraction， but only recently in California has it become profitable to pump water from this depth. The aquifers range from 1，000 to 3，000 feet below the ground， which means that pumping will be expensive and there are other concerns. 48.The biggest concern of pumping out water from this deep in the gradual settling down of the land surface. As the water is pumped out， the vacant space left is compacted by the weight of the earth above.

　　Even though pumping from these depths is expensive， it is still cheaper than desalinating（脱盐）the ocean water in the largely coastal state. Some desalination plants exist where feasible， but they are costly to run and can need constant repairs.49. Wells are much more reliable sources of freshwater， and California is hoping that these deep wells may be the answer to their severe water shortage.One problem with these sources is that the deep water also has a higher level of salt than shallower aquifers. 50.This means that some wells may even need to undergo desalination after extraction， thus increasing the cost. Research from the exhaustive study of groundwater from over 950 drilling logs has just been published. New estimates of the water reserves now go up to 2，700 billion cubic meters of freshwater.

　　46.How could California‘s drought crisis be solved according to some researchers？

　　A) By building more reserves of groundwater.

　　B) By drawing water from the depths of the earth.

　　C) By developing more advanced drilling devices.

　　D) By upgrading its water distribution system.

　　答案：B

　　解析：细节题

　　利用题干关键词定位文章第一段，通过关键词found 确定重点内容为deep water reserves under the state which could help solve their drought crisis.以及后文的数据实验作为例证，可知危机可通过开采地下水解决。于是B选项同义替换。A选项偷换概念，并没有建立更多的动作。C选项无中生有原文并未提及先进的钻井技术。D选项无中生有，并未提及水利调配体系。

　　47.What can be inferred about extracting water from deep aquifers？

　　A) It was deemed vital to solving the water problem.

　　B) It was not considered worth the expense.

　　C) It may not provide quality freshwater.

　　D) It is bound to gain support from the local people.

　　答案：B

　　解析：推理题

　　根据题干定位到第一段划线部分but due to new pumping practices， water deeper than this can now be extracted （抽取）. The team at Stanford investigated the aquifers（地下蓄水层）below this depth and found that reserves may be triple what was previously thought.解题关键词依旧为found，因为此题目为推理题，于是答案应当为原文的间接表达。原文中说地下水的储备量超过了预期的三倍。于是可以判断之前对于地下水量的态度较为保守，认为不应该进行开采，于是选择B选项。A选项与原文意见相反。C、D均为无中生有。

　　48. What is mentioned as a consequence of extracting water from deep underground？

　　A) The sinking of land surface.          C) The damage to aquifers.

　　B) The harm to the ecosystem.         D) The change of the climate.

　　答案：A

　　解析：细节题

　　此题目按照顺序原则回文定位，可发现题干论述过于抽象，课利用选项短语回文定位The biggest concern of pumping out water from this deep in the gradual settling down of the land surface. As the water is pumped out， the vacant space left is compacted by the weight of the earth above.其中只有A选项符合文意，为同义替换+原词选项。B、C、D均未提及。

　　49. What does the author say about deep wells？

　　A) They run without any need for repairs.

　　B) They are entirely free from pollutants.

　　C) They are the ultimate solution to droughts.

　　D) They provide a steady supply of freshwater.

　　答案：D

　　解析：细节题

　　利用顺序原则，将题干定位到文中划线位置Wells are much more reliable sources of freshwater， and California is hoping that these deep wells may be the answer to their severe water shortage 可知D选项为原词+同义替换。A、B、均未提及。C选项偷换概念，将answer替换成了ultimate solution。

　　50. What may happen when deep aquifers are used as water sources？

　　A) People’s health may improve with cleaner water.

　　B) People‘s water bills may be lowered considerably.

　　C) The cost may go up due to desalination.

　　D) They may be exhausted sooner or later.

　　答案：C

　　解析：细节题

　　利用文章剩下内容，讲关键词锁定在problem、means、thus因此可将解题句确定在This means that some wells may even need to undergo desalination after extraction， thus increasing the cost. C选项为原文。A、B、D无中生有。