As more and more of the known reserves of oil get used up, the present value of each barrel of the remaining oil begins to rise and, once more, exploration for additional oil becomes profitable.

随着越来越多的已知石被耗尽，每桶剩余石的现值开始上升，勘探更多石再次变得有利可图。

In places such as San Diego, which has measly and brackish groundwater and currently imports 90% of its water, the answer must be greater conservation, as much reuse as possible, with most of the rest coming from the sea.

圣亚哥拥有的下水既少，盐份又高，如今其90%的用水需从外。在像圣亚哥这样的方，其对策是尽可能的节约用水、循环利用，而剩余不足的部份则大多从海洋中获取。