California has been facing a drought for many years now, with certain areas even having to pump freshwater hundreds of miles to

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问题    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. 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, 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. The biggest concern of pumping out water from this deep is 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. 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. 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.  
What can be inferred about extracting water from deep aquifers?

选项 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。由原文第二段可知,最近在加州从深层蓄水层用泵抽水变得有合算了。从地下1000到3000英尺的地方抽水的成本很高,而且还同时伴随着其他一些问题。最大的顾虑是地表会逐渐下陷。由此可知,以前人们认为从深层蓄水层用泵抽水成本高,还可能引起地表下沉,代价太大,不值得,故答案为B。原文第一段只表明地下深水可以帮助解决危机,无法推断其重要性,而且这是最近的研究发现的,而不是以前意识到的,故排除A项。由第四段可知,含盐量较高的水只是有些深井可能会现的,一般深井中的水质量可能还是优质的,故排除C项。D项原文未提及,故排除。
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