付文杰的回答：
Benxi Benxi tunnel tunnel guides the original word "Galaxy nine holes." Underground river is a large underground karst cave, with a total length 5km. Tourism has been the development of a long tunnel for 2438.4m, an area of 45,000 square meters, the volume of 390,000 cubic meters, a large cave, all kinds of karst landscape is both varied and impressive seven Palace, the Three Gorges, 2, 9 more than King. Long underground river underground smooth, boat览胜, such as into fairyland. Benxi Water Cave is currently the world"s longest cave tour, one of the water. approval of the State Council in 1994 as a national key scenic spots. Benxi Water Cave Tour can not only enjoy the uncanny workmanship of nature created by the fantastic beauty of magic, and you also get a lot of holes in scientific knowledge. Karst cave, also known as karst cave. "Karst" is derived from the Federal Republic of Yugoslavia (Yugoslavia) of the karst plateau. Where strange landscape, in the limestone caves in the formation of the concerns of scientists. Since then, all phenomena are better described as "karst." The object of scientific study called "karst and cave science learning. Karst caves in soluble rocks, especially carbonate rocks of limestone and dolomite rock which, because of the long-term dissolution of water formed. Nature of water is not pure water, water containing carbon dioxide, when water containing carbon dioxide when limestone encountered in limestone fissures occur in the flow of carbonation reaction of calcium bicarbonate, the calcium bicarbonate dissolved in water, therefore water away, with the passage of time, corrosion cracks have been into the cave. The world"s longest karst cave, Kentucky United States dong the Ma-Mongolian groups (Meng犸cave Mamofh Cave System), the hole from the beginning of the investigation in 1802, after 180 years to find out the length of 550Km.
覃俊的回答：
