The concept of obtaining fresh water from icebergs that are pulled to populated areas and dry regions of the world was once trea

admin2013-05-19  37

问题     The concept of obtaining fresh water from icebergs that are pulled to populated areas and dry regions of the world was once treated as a joke more appropriate to cartoons than real life. But now it is being considered quite seriously by many nations, especially since scientists have warned that human race will outgrow its fresh water supply faster than it runs out of food.
    Glaciers are a possible source of fresh water that has been overlooked until recently. Three quarters of the Earth’s fresh water supply is still tied up in glacial ice, a reservoir of untapped fresh water so immense that it could sustain all the rivers of the world for 1,000 years. Floating on the oceans are 7,659 trillion metric tons of ice encased (包围) in 10,000 icebergs that break away from the polar ice caps, more than ninety percent of them from Antarctica.
    Huge glaciers that stretch over the shallow continental shelf give birth to icebergs throughout the year. Icebergs are not like sea ice, which is formed when the sea itself freezes; rather, they are formed entirely on land, breaking off when glaciers spread over the sea. As they drift away from the polar region, icebergs sometimes move mysteriously in a direction opposite to the wind, pulled by subsurface currents. Because they melt more slowly than smaller pieces of ice, icebergs have been known to drift as far north as 35 degrees south of the equator in the Atlantic Ocean. To corral them and steer them to parts of the world where they are needed would not be too difficult.
    The difficulty arises in other technical matters, such as the prevention of rapid melting in warmer climates and the funneling (通过漏斗般流过) of fresh water to shore in great volume. But even if the icebergs lost half of their volume in hauling, the water they could provide would be far cheaper than that produced by desalinating (融化海水), or removing salt from water.
With which of the following ideas would the author be likely to agree?

选项 A、Pulling icebergs to dry area is economically possible.
B、Desalination of water is the best way to obtain drinking water.
C、Using water from icebergs is a very short-term solution to water shortages.
D、Icebergs could not be hauled very far before they would melt.

答案A

解析 末段末句提到But…the water they could provide would be far cheaper than that produced by desalinating(淡化海水),or removing salt from water,由此可知,作者认为从冰山中获取淡水比海水淡化省钱,即把冰山拖到干旱地区在经济上是可行的,故答案为[A],同时排除[B]。文章第二段第二句提到,冰川就是一个蓄水池,其中未开发的淡水量是如此巨大,足够支持全世界的淡水河1,000年,[C]中的a very short-term与1,000 years不符,故排除。[D]与第三段末句提到的“将这些冰山运送到需要它们的地方并不难”矛盾,故排除。
转载请注明原文地址:https://kaotiyun.com/show/mTg7777K
0

最新回复(0)