编辑点评: 研习GRE作文考试的优秀范文不仅可以学到有用的词汇和句子,更能从中学习逻辑的构建方式和作文框架的结构等内容,这里为大家提供GRE的范文,希望对同学们的备考有所帮助。
The concept of obtaining fresh water from icebergs that are towed to populated areas and arid 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 the 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 every year are 7,659 trillion metric tons of ice encased in 10000 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 of fresh water to shore in great volume. But even if the icebergs lost half of their volume in towing, the water they could provide would be far cheaper than that produced by desalinization, or removing salt from water.
下一篇: GRE写作范文——Bacteria
Relations between Britain and its American colonies
Growing girls who code
President Obama wins second term
Mae West, the wild woman of film and stage
Edwin Hubble changed our ideas about the universe
Can you 'think and grow rich?'
Words and their stories: top brass
Obama, House Speaker take positions on budget before negotiations
A story for Halloween: 'Innocence Burned'
Did hurricane Sandy send a climate warning?
Taylor Swift's 'Red' among 2012's best sellers
American Red Cross feeds hungry after hurricane
Hurricane Sandy reignites climate change debate
Eleanor Creesy helped guide one of the fastest sailing ships ever built
Florida Seniors split on medicare debate
Scientists dispute study of genetically modified corn
Gas shortages test patience of motorists following Sandy
Make-your-own soap entrepreneurs clean up
Global warming might threaten water supply
Breathe Carolina re-releases
Number of international students attending American colleges and universities continues rising
Puberty lessons for African girls may raise attendance
Psychologist tells inspiring story of his giant uncle
Low-lying areas of New York City suffer flooding
Is eating like our ancestors good for us?
Condition of oceans affects human health
New 007 movie reveals Bond's inner demo
After Sandy, Wall Street closed for 2nd day
Medical students help the homeless
Obama victory driven by economy, turnout