『新东方在线托福阅读』为托福考生准备了ETS托福TPO/【学术文章】#22阅读练习：Which of the following does the author mention as a possible cause of surging glaciers?真题题目及答案解析，TPO/【学术文章】#22阅读原文范文音频翻译

托福TPO/【学术文章】#22阅读原文Which of the following does the author mention as a possible cause of surging glaciers?题目答案及解析-新东方托福官方网校手机版

The word “intervals” is closest in meaning to

Why does the author compare the surging motion of a glacier to a wave?

Which of the following does the author mention as a possible cause of surging glaciers?

According to the passage, what distinguishes surge glaciers from normal glaciers located nearby?

The Unpredictable Surge of Glaciers During most of their lives, surge glaciers behave like normal glaciers, traveling perhaps only a couple of inches per day. However, at intervals of 10 to 100 years, these glaciers move forward up to 100 times faster than usual. The surge often progresses along a glacier like a great wave, proceeding from one section to another. Subglacial streams of melt water pressure under the glacier might lift it off its bed, overcoming the friction between ice and rock, thus freeing the glacier, which rapidly slides downhill. Surge glaciers also might be influenced by the climate, volcanic heat, or earthquakes. Some 800 years ago, Alaska’s Hubbard Glacier advanced toward the sea, retreated, and advanced again 500 years later. Since 1895, this seventy-mile-long river of ice has been flowing steadily toward the Gulf of Alaska at a rate of approximately 200 feet per year. In June 1986, however, the glacier surged ahead as much as 47 feet a day. Meanwhile, a western tributary, called Valerie Glacier, advanced up to 112 feet a day. Hubbard’s surge closed off Russell Fiord with a formidable ice dam, whose caged waters threatened the town of Yakutat. About 20 similar glaciers around the Gulf of Alaska are heading toward the sea. If enough surge glaciers reach the ocean and raise sea levels, a flood of ice would surge into the Southern Sea. The additional sea ice floating toward the tropics would increase Earth’s albedo and lower global temperatures, perhaps enough to initiate a new ice age.