托福考试

【单选题】1
A、hot spot is a giant underground caldron of molten rock in one of the world’s many volcanically active areas. The steamy~ geysers, thermal pools, and mud pots of Yellowstone National Park owe their origins to hot spots.
2Annually, more than 200 geysers erupt in Yellowstone, making this one of the most interesting places in the world for geologists. Over 100 geysers lie within the Upper GeyserBasin, a one-square-mile area near Old Faithful, the most famous geyser in the worlD、The Yellowstone hot spot was created around ten million years ago, and the center of the park is still volcanically active, with molten rock only a mile or two beneath theEarth’s surface.
3 When rain and melted snow seep down through tiny cracks in theEarth, the water eventually reaches underground chambers of lava-heated rock. The rock heats the water, and the boiling water and steam often make their way back up to the surface in the form of a geyser, a thermal pool, or a mud pot.
4 In a geyser, water trapped in an underground chamber heats up beyond the boiling point and forms steam. Since steam takes up 1,500 times more space than water, pressure builds up, eventually forcing the superheated water to burst to the surface as a geyser.
A、thermal pool is formed when the water from the hot spot reaches the surface before cooling off. If the water does not make it all the way to the surface, steam and gases may dissolve rocks and form a bubbling mud pot insteaD、
When do mud pots form
A、When steam and gases dissolve rocks near the surface
B．When underground water exceeds the boiling point
C．When snow melts in Yellowstone’s geyser basins
D．When superheated water bursts to the surface

网考网参考答案：A
网考网解析：
Clues: If the water does not make it all the way to the surface, steam and gases may dissolve rocks and form a bubbling mud pot instead. document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>