题目内容：

    California has been facing droughts for many years, 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 three times what was previously thought.

It is profitable to drill to depths more than 1,000 feet for oil and gas, 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 is the gradual setting down of the land surface. As the water is pumped out, the vacant space left is pressed 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 possible, 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 water may even need to be desalinated after extraction, thus increasing the cost. Research from the study of groundwater has just been published. New estimates of the water reserves now go up to 2,700 billion cubic meters of freshwater.

1.According to the text, what causes the water crisis in California?

A.Previous drilling of wells. B.The messy distribution system.

C.Constant droughts in the area. D.The adoption of new pumping practices.

2.The research teams think it ________ to extract water from deeper aquifers.

A.expensive but practical B.reliable and profitable

C.cost-free but demanding D.cheap and environment-friendly

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

A.The damage to aquifers. B.The sinking of land surface.

C.The decrease in operation costs. D.The negative effects on the climate.

4.What is the author’s purpose in writing the text?

A.To encourage people to save water.

B.To promote the seawater desalination.

C.To introduce a new way of extracting freshwater.

D.To draw people’s attention to the droughts in California.