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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. What is the main topic of the passage
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案例分析题Many people believe they should drink eight glasses of water a day. That is (41) they have been told all their life. (42) a new report says people should drink as (43) water as they feel like drinking. The report does not (44) people how many glasses of water to drink. Instead, (45) says women should get about 2.7 litres (升) of water a day, (46) that men should get about 3.7 litres. In each (47) , that is more than eight glasses. As you might (48) , the report says people need to drink more water (49) they are doing physical (体力的) work. The same is true of those who live in hot weather. These people could need much more water (50) others. 43（）。
Halfway through the semester in his market research course at Roanoke College last fall, only moments after announcing a policy of zero tolerance for cellphone use in the classroom, Prof. Ali Nazemi heard a ring. Then he spotted a young man named Neil Noland fumbling with his phone, trying to turn it off before being caught. "Nell, can I see that phone" Professor Nazemi said, more in a command than a question. The student surrendered it. Professor Nazemi opened his briefcase, produced a hammer and proceeded to smash the offending device. Throughout the classroom, student faces went ashen. "How am I going to call my Morn now" Neil asked. As Professor Nazemi refused to answer, a classmate offered, "Dude, you can sue. " One thing we should be clear about was the episode in his classroom had been plotted and scripted ahead of time, with Nell Noland part of the charade all along. The phone was an extra of his mother’s, its service contract long expired. Professor Nazemi, in a telephone interview last week, attested to the exasperation of countless teachers and professors in the computer era. Their permanent war of attrition with defiantly inattentive students has escalated from the pursuit of pigtail-pulling, spitball-lobbing and notebook-doodling to a high-tech arsenal of laptops, cellphones Blackberries and the like. The poor school teacher or master or master now must compete with texting, instant- messaging, Facebook, eBay, YouTube, Addictinggames. Corn and other poxes(瘟疫，灾难)on pedagogy. "There are certain lines you shouldn’t cross," the professor said. If you start tolerating this stuff, it becomes the norm. "The more you give, the more they take. Multitasking is good, but I want them to do more tasking in my class. " All the advances schools and colleges have made to supposedly enhance learning— supplying students with laptops, equipping computer labs, creating wireless networks— have insteadenabled distraction. Perhaps attendance records should include a new category: present but otherwise engaged. "I am so tired of that excuse," said Professor Bugeja, may he live a long and fruitful life. "The idea that subject matter is boring is truly relative. Boring as opposed to what Buying shoes on eBay The fact is, we’re not here to entertain. We are here to stimulate the life of the mind. " "Education requires contemplation," he continued. "It requires critical thinking. What we may be doing now is training a generation of air-traffic controllers rather than scholars. And I do know I’m going to lose. " Not, one can only hope, without fight. In the end, as science-fiction writers have prophesied for years, the technology is bound to outwit the fallible human. What teacher or professor can possibly police a room full of determined goof-offs(游手好闲者)while also delivering an engaging lesson "I am so tired of that excuse," said Professor Bugeja, may he live a long and fruitful life. "The idea that subject matter is boring is truly relative. Boring as opposed to what Buying shoes on eBay The fact is, we’re not here to entertain. We are here to stimulate the life of the mind. "
社会主义初级阶段的基本经济制度是（）。
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. With which of the following ideas would the author be likely to agree
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