1 . If you’ve ever worried that we’ve solved all the mysteries of nature, fear not. Minnesota’s Devil’s Kettle Falls has been attracting hikers and geologists for generations. At the falls, along Lake Superior’s North shore, a river forks at a rock outcrop. While one side runs down a two-step stone bank and continues on like a normal waterfall, the other side falls into a deep hole and disappears apparently forever.
And this baffling situation only gets strange when geologists start explaining Devil’s Kettle (水壶). Consider, for instance, the sheer quantity of water pouring into the kettle every minute of every day. While the idea of some kind of broad, underground river is an exciting device in movies, the reality is that those sorts of deep caves are rare.
Another idea is that millions of years ago, a hollow lava tube may have formed beneath the falls, in the subsurface layer of rock. Over time, the theory suggests, the falling water eroded (侵蚀) the surface and fell straight down into the ancient lava tube, providing wide-open access to the floor of Lake Superior. Again, there are problems with this theory, because no lava tubes have ever been found in any of the hundreds of exposed rock beds in the area.
In February 2017, scientists said that water that disappears into the rock at Devil’s Kettle rises again in the stream below the falls. To confirm the theory, scientists plan on conducting a dye trace during a low-water flow period. They’ll pour a vegetable-based dye into the pothole and watch where the dye comes to the surface again.
“What we think is happening is that the water is going in the kettle, and coming up pretty close to immediately downstream of the falls,” Green said.
Green admits that if the dye is found below the falls like the scientists suspect, then much of the Devil’s Kettle Falls mystery will be gone. “Were there a little bit of that,” he said, “the folks would not be going to stand there and wonder. But it will still be a fascinating spot, and a beautiful spot.”
1. What is the purpose of writing the first paragraph?| A．To explain the formation of waterfalls. |
| B．To describe a beautiful landscape scene. |
| C．To introduce a mysterious natural phenomenon. |
| D．To recommend an unusual waterfall to readers. |
| A．Supportive. | B．Curious. | C．Doubtful. | D．Indifferent. |
| A．By tracing the path of the water. |
| B．By controlling the direction of the stream. |
| C．By asking the folks to watch the surface. |
| D．By filling the pothole with a dye. |
| A．The mystery of Devil’s Kettle Falls |
| B．The discovery of Devil’s Kettle Falls |
| C．The disappearance of Devil’s Kettle Falls |
| D．The fascinating features of Devil’s Kettle Falls |
