Seismologist David Oppenheimer of’ the U. S. Geological Survey Earthquakes Hazards Team explains (as told to Katherine Harmon) : Traditional geothermal drilling bores into hot rock such as sandstone that has water or steam trapped in its pore spaces and natural fractures. When a drilled hole intersects these fractures, the water flashes into steam because of the sudden drop in pressure-like bubbles that come out of a soda bottle when the cap is removed. The steam surges into the well hole, and the steam pressure at the surface spins a turbine to generate electricity. Sometimes the plant returns some of the water back into the reservoir to keep water levels up. The drilling itself does not cause earthquakes, but the steam removal and water return can do so, by producing new instability along fault or fracture lines.
(41)______________________ Researchers know they result from steam withdrawal or injection because when operators begin geothermal production in a new area, earthquakes begin and when production ends, the earthquakes stop. Many minor tremors occur, but quakes as large as magnitude 4.5 have been recorded. Residents of nearby Anderson Springs often feel tremors as small as magnitude 2.0 because the town sits only a couple of kilometers above the rock fractures.
(42) ______________ When a large earthquake does occur, the public will ask whether the geothermal projects might have played a role in causing the rocks to shift along other faults. And researchers will have to use geodetic monitoring and other data to try to figure out whether it really was a factor in changing key stress dynamics.
(43) ______________ Because the felsite has no natural pores, it also contains no water. To recover the heat, the project’s operators would have needed to fracture the rock and circulate water through it.
First, in the short phase of the project, they would have drilled into the felsite and injected water to fracture the rock, most likely generating earthquakes in the process. Then, aided by borehole cameras revealing in which direction the fractures formed, they would have drilled a second hole to intersect the new fractures and would have produced steam by pumping water through the hot fractures linking the wells. This dry-rock geothermal approach has the potential to harness much more heat than the traditional sandstone techniques, but it can also mean more earthquakes.
(44)______________.
Unfortunately, areas that are less tectonically active also have less accessible subterranean heat sources. (45)______________.

[A] California, for example, has more heat (because of its location near tectonic plate margins) than, say, Texas. The whole country has some geothermal potential if we wanted to draw warmth for heating. But the resulting heat would not necessarily have the energy to spin large turbines for electricity generation.
[B] At a long-term geothermal project in northern California known as the Geysers, the USGS has been monitoring seismic activity since 1975. Even though the area does not appear to have any large faults running through it, esearchers record about 4,000 quakes above magnitude 1.0 every year.
[C] All sources of energy-hydropower, nuclear, wind or coal—have advantages and disadvantages. Geothermal energy has the advantage of being clean and renewable, but earthquakes are a downside.
[D] In addition to the traditional geothermal plants at the Geysers, a pilot project, which was suspended last September, intended to draw steam directly from the volcanic, nonporous rock called Msite that lies below the sandstone and is its heat source.
[E] To control the earthquake risk, drillers would have tried to keep the size of the fractures small and to maintain steady water flow rates. The threshold goal for earthquakes is 2.0 or lower on the Richter scale. Such deep-drilling operations would not want a repeat of events in Basel, Switzerland, where a widely felt magnitude 3.4 quake in 2006 ultimately stopped a similar geothermal project.
[F] Many researches have been finished during the past years, and the relationship between the earthquake and Geothermal energy has been proved, which orientated the direction to the use of Geothermal energy.[E] Geologists suspect that even larger earthquakes could occur on nearby faults such as the Maacama, which is adjacent to the Geysers fields. The extraction of water and heat from the porous sandstone causes it to contract, much as a sponge shrinks when it dries out.

Seismologist David Oppenheimer of’ the U. S. Geological Survey Earthquakes Hazards Team explains (as told to Katherine Harmon) : Traditional geothermal drilling bores into hot rock such as sandstone that has water or steam trapped in its pore spaces and natural fractures. When a drilled hole intersects these fractures, the water flashes into steam because of the sudden drop in pressure-like bubbles that come out of a soda bottle when the cap is removed. The steam surges into the well hole, and the steam pressure at the surface spins a turbine to generate electricity. Sometimes the plant returns some of the water back into the reservoir to keep water levels up. The drilling itself does not cause earthquakes, but the steam removal and water return can do so, by producing new instability along fault or fracture lines.
(41)______________________ Researchers know they result from steam withdrawal or injection because when operators begin geothermal production in a new area, earthquakes begin and when production ends, the earthquakes stop. Many minor tremors occur, but quakes as large as magnitude 4.5 have been recorded. Residents of nearby Anderson Springs often feel tremors as small as magnitude 2.0 because the town sits only a couple of kilometers above the rock fractures.
(42) ______________ When a large earthquake does occur, the public will ask whether the geothermal projects might have played a role in causing the rocks to shift along other faults. And researchers will have to use geodetic monitoring and other data to try to figure out whether it really was a factor in changing key stress dynamics.
(43) ______________ Because the felsite has no natural pores, it also contains no water. To recover the heat, the project’s operators would have needed to fracture the rock and circulate water through it.
First, in the short phase of the project, they would have drilled into the felsite and injected water to fracture the rock, most likely generating earthquakes in the process. Then, aided by borehole cameras revealing in which direction the fractures formed, they would have drilled a second hole to intersect the new fractures and would have produced steam by pumping water through the hot fractures linking the wells. This dry-rock geothermal approach has the potential to harness much more heat than the traditional sandstone techniques, but it can also mean more earthquakes.
(44)______________.
Unfortunately, areas that are less tectonically active also have less accessible subterranean heat sources. (45)______________.

[A] California, for example, has more heat (because of its location near tectonic plate margins) than, say, Texas. The whole country has some geothermal potential if we wanted to draw warmth for heating. But the resulting heat would not necessarily have the energy to spin large turbines for electricity generation.
[B] At a long-term geothermal project in northern California known as the Geysers, the USGS has been monitoring seismic activity since 1975. Even though the area does not appear to have any large faults running through it, esearchers record about 4,000 quakes above magnitude 1.0 every year.
[C] All sources of energy-hydropower, nuclear, wind or coal—have advantages and disadvantages. Geothermal energy has the advantage of being clean and renewable, but earthquakes are a downside.
[D] In addition to the traditional geothermal plants at the Geysers, a pilot project, which was suspended last September, intended to draw steam directly from the volcanic, nonporous rock called Msite that lies below the sandstone and is its heat source.
[E] To control the earthquake risk, drillers would have tried to keep the size of the fractures small and to maintain steady water flow rates. The threshold goal for earthquakes is 2.0 or lower on the Richter scale. Such deep-drilling operations would not want a repeat of events in Basel, Switzerland, where a widely felt magnitude 3.4 quake in 2006 ultimately stopped a similar geothermal project.
[F] Many researches have been finished during the past years, and the relationship between the earthquake and Geothermal energy has been proved, which orientated the direction to the use of Geothermal energy.[E] Geologists suspect that even larger earthquakes could occur on nearby faults such as the Maacama, which is adjacent to the Geysers fields. The extraction of water and heat from the porous sandstone causes it to contract, much as a sponge shrinks when it dries out.

Seismologist David Oppenheimer of’ the U. S. Geological Survey Earthquakes Hazards Team explains (as told to Katherine Harmon) : Traditional geothermal drilling bores into hot rock such as sandstone that has water or steam trapped in its pore spaces and natural fractures. When a drilled hole intersects these fractures, the water flashes into steam because of the sudden drop in pressure-like bubbles that come out of a soda bottle when the cap is removed. The steam surges into the well hole, and the steam pressure at the surface spins a turbine to generate electricity. Sometimes the plant returns some of the water back into the reservoir to keep water levels up. The drilling itself does not cause earthquakes, but the steam removal and water return can do so, by producing new instability along fault or fracture lines.
(41)______________________ Researchers know they result from steam withdrawal or injection because when operators begin geothermal production in a new area, earthquakes begin and when production ends, the earthquakes stop. Many minor tremors occur, but quakes as large as magnitude 4.5 have been recorded. Residents of nearby Anderson Springs often feel tremors as small as magnitude 2.0 because the town sits only a couple of kilometers above the rock fractures.
(42) ______________ When a large earthquake does occur, the public will ask whether the geothermal projects might have played a role in causing the rocks to shift along other faults. And researchers will have to use geodetic monitoring and other data to try to figure out whether it really was a factor in changing key stress dynamics.
(43) ______________ Because the felsite has no natural pores, it also contains no water. To recover the heat, the project’s operators would have needed to fracture the rock and circulate water through it.
First, in the short phase of the project, they would have drilled into the felsite and injected water to fracture the rock, most likely generating earthquakes in the process. Then, aided by borehole cameras revealing in which direction the fractures formed, they would have drilled a second hole to intersect the new fractures and would have produced steam by pumping water through the hot fractures linking the wells. This dry-rock geothermal approach has the potential to harness much more heat than the traditional sandstone techniques, but it can also mean more earthquakes.
(44)______________.
Unfortunately, areas that are less tectonically active also have less accessible subterranean heat sources. (45)______________.

[A] California, for example, has more heat (because of its location near tectonic plate margins) than, say, Texas. The whole country has some geothermal potential if we wanted to draw warmth for heating. But the resulting heat would not necessarily have the energy to spin large turbines for electricity generation.
[B] At a long-term geothermal project in northern California known as the Geysers, the USGS has been monitoring seismic activity since 1975. Even though the area does not appear to have any large faults running through it, esearchers record about 4,000 quakes above magnitude 1.0 every year.
[C] All sources of energy-hydropower, nuclear, wind or coal—have advantages and disadvantages. Geothermal energy has the advantage of being clean and renewable, but earthquakes are a downside.
[D] In addition to the traditional geothermal plants at the Geysers, a pilot project, which was suspended last September, intended to draw steam directly from the volcanic, nonporous rock called Msite that lies below the sandstone and is its heat source.
[E] To control the earthquake risk, drillers would have tried to keep the size of the fractures small and to maintain steady water flow rates. The threshold goal for earthquakes is 2.0 or lower on the Richter scale. Such deep-drilling operations would not want a repeat of events in Basel, Switzerland, where a widely felt magnitude 3.4 quake in 2006 ultimately stopped a similar geothermal project.
[F] Many researches have been finished during the past years, and the relationship between the earthquake and Geothermal energy has been proved, which orientated the direction to the use of Geothermal energy.[E] Geologists suspect that even larger earthquakes could occur on nearby faults such as the Maacama, which is adjacent to the Geysers fields. The extraction of water and heat from the porous sandstone causes it to contract, much as a sponge shrinks when it dries out.

Seismologist David Oppenheimer of’ the U. S. Geological Survey Earthquakes Hazards Team explains (as told to Katherine Harmon) : Traditional geothermal drilling bores into hot rock such as sandstone that has water or steam trapped in its pore spaces and natural fractures. When a drilled hole intersects these fractures, the water flashes into steam because of the sudden drop in pressure-like bubbles that come out of a soda bottle when the cap is removed. The steam surges into the well hole, and the steam pressure at the surface spins a turbine to generate electricity. Sometimes the plant returns some of the water back into the reservoir to keep water levels up. The drilling itself does not cause earthquakes, but the steam removal and water return can do so, by producing new instability along fault or fracture lines.
(41)______________________ Researchers know they result from steam withdrawal or injection because when operators begin geothermal production in a new area, earthquakes begin and when production ends, the earthquakes stop. Many minor tremors occur, but quakes as large as magnitude 4.5 have been recorded. Residents of nearby Anderson Springs often feel tremors as small as magnitude 2.0 because the town sits only a couple of kilometers above the rock fractures.
(42) ______________ When a large earthquake does occur, the public will ask whether the geothermal projects might have played a role in causing the rocks to shift along other faults. And researchers will have to use geodetic monitoring and other data to try to figure out whether it really was a factor in changing key stress dynamics.
(43) ______________ Because the felsite has no natural pores, it also contains no water. To recover the heat, the project’s operators would have needed to fracture the rock and circulate water through it.
First, in the short phase of the project, they would have drilled into the felsite and injected water to fracture the rock, most likely generating earthquakes in the process. Then, aided by borehole cameras revealing in which direction the fractures formed, they would have drilled a second hole to intersect the new fractures and would have produced steam by pumping water through the hot fractures linking the wells. This dry-rock geothermal approach has the potential to harness much more heat than the traditional sandstone techniques, but it can also mean more earthquakes.
(44)______________.
Unfortunately, areas that are less tectonically active also have less accessible subterranean heat sources. (45)______________.

[A] California, for example, has more heat (because of its location near tectonic plate margins) than, say, Texas. The whole country has some geothermal potential if we wanted to draw warmth for heating. But the resulting heat would not necessarily have the energy to spin large turbines for electricity generation.
[B] At a long-term geothermal project in northern California known as the Geysers, the USGS has been monitoring seismic activity since 1975. Even though the area does not appear to have any large faults running through it, esearchers record about 4,000 quakes above magnitude 1.0 every year.
[C] All sources of energy-hydropower, nuclear, wind or coal—have advantages and disadvantages. Geothermal energy has the advantage of being clean and renewable, but earthquakes are a downside.
[D] In addition to the traditional geothermal plants at the Geysers, a pilot project, which was suspended last September, intended to draw steam directly from the volcanic, nonporous rock called Msite that lies below the sandstone and is its heat source.
[E] To control the earthquake risk, drillers would have tried to keep the size of the fractures small and to maintain steady water flow rates. The threshold goal for earthquakes is 2.0 or lower on the Richter scale. Such deep-drilling operations would not want a repeat of events in Basel, Switzerland, where a widely felt magnitude 3.4 quake in 2006 ultimately stopped a similar geothermal project.
[F] Many researches have been finished during the past years, and the relationship between the earthquake and Geothermal energy has been proved, which orientated the direction to the use of Geothermal energy.[E] Geologists suspect that even larger earthquakes could occur on nearby faults such as the Maacama, which is adjacent to the Geysers fields. The extraction of water and heat from the porous sandstone causes it to contract, much as a sponge shrinks when it dries out.

Seismologist David Oppenheimer of’ the U. S. Geological Survey Earthquakes Hazards Team explains (as told to Katherine Harmon) : Traditional geothermal drilling bores into hot rock such as sandstone that has water or steam trapped in its pore spaces and natural fractures. When a drilled hole intersects these fractures, the water flashes into steam because of the sudden drop in pressure-like bubbles that come out of a soda bottle when the cap is removed. The steam surges into the well hole, and the steam pressure at the surface spins a turbine to generate electricity. Sometimes the plant returns some of the water back into the reservoir to keep water levels up. The drilling itself does not cause earthquakes, but the steam removal and water return can do so, by producing new instability along fault or fracture lines.
(41)______________________ Researchers know they result from steam withdrawal or injection because when operators begin geothermal production in a new area, earthquakes begin and when production ends, the earthquakes stop. Many minor tremors occur, but quakes as large as magnitude 4.5 have been recorded. Residents of nearby Anderson Springs often feel tremors as small as magnitude 2.0 because the town sits only a couple of kilometers above the rock fractures.
(42) ______________ When a large earthquake does occur, the public will ask whether the geothermal projects might have played a role in causing the rocks to shift along other faults. And researchers will have to use geodetic monitoring and other data to try to figure out whether it really was a factor in changing key stress dynamics.
(43) ______________ Because the felsite has no natural pores, it also contains no water. To recover the heat, the project’s operators would have needed to fracture the rock and circulate water through it.
First, in the short phase of the project, they would have drilled into the felsite and injected water to fracture the rock, most likely generating earthquakes in the process. Then, aided by borehole cameras revealing in which direction the fractures formed, they would have drilled a second hole to intersect the new fractures and would have produced steam by pumping water through the hot fractures linking the wells. This dry-rock geothermal approach has the potential to harness much more heat than the traditional sandstone techniques, but it can also mean more earthquakes.
(44)______________.
Unfortunately, areas that are less tectonically active also have less accessible subterranean heat sources. (45)______________.

[A] California, for example, has more heat (because of its location near tectonic plate margins) than, say, Texas. The whole country has some geothermal potential if we wanted to draw warmth for heating. But the resulting heat would not necessarily have the energy to spin large turbines for electricity generation.
[B] At a long-term geothermal project in northern California known as the Geysers, the USGS has been monitoring seismic activity since 1975. Even though the area does not appear to have any large faults running through it, esearchers record about 4,000 quakes above magnitude 1.0 every year.
[C] All sources of energy-hydropower, nuclear, wind or coal—have advantages and disadvantages. Geothermal energy has the advantage of being clean and renewable, but earthquakes are a downside.
[D] In addition to the traditional geothermal plants at the Geysers, a pilot project, which was suspended last September, intended to draw steam directly from the volcanic, nonporous rock called Msite that lies below the sandstone and is its heat source.
[E] To control the earthquake risk, drillers would have tried to keep the size of the fractures small and to maintain steady water flow rates. The threshold goal for earthquakes is 2.0 or lower on the Richter scale. Such deep-drilling operations would not want a repeat of events in Basel, Switzerland, where a widely felt magnitude 3.4 quake in 2006 ultimately stopped a similar geothermal project.
[F] Many researches have been finished during the past years, and the relationship between the earthquake and Geothermal energy has been proved, which orientated the direction to the use of Geothermal energy.[E] Geologists suspect that even larger earthquakes could occur on nearby faults such as the Maacama, which is adjacent to the Geysers fields. The extraction of water and heat from the porous sandstone causes it to contract, much as a sponge shrinks when it dries out.

Explore Jordan Wadi Rum is the name given to a valley cut into the sandstone and hard rock in southwest Jordan. _____（46） The name Rum most likely comes from an Aramaic word meaning “high” or “elevated”, The area around Wadi Rum is now also one of Jordan’s most important tourist destinations, and attracts an increasing number of foreign tourists, particularly trekkers（越野者），but also for camel safaris（旅行） or simply day-trippers from Aqaba or Petra. In contrast, there are almost no local or Arab tourists through Popular activities in the desert environment include camping under the stars ,riding Arab horses ,and rock-climbing amongst the massive rock formations .Jebal Rum(Jebal means mountain )is 1574 metres above sea level. _____（47）. But Jordan is not simply a desert environment ——it also contains the area which is the lowest point to the face of the Earth ——the incredible Dead Sea, popular with tourists for swimming. _____（48） Once the waters reach the Dead Sea they are landlocked and have nowhere to go, so they evaporate ,leaving behind a dense ,rich cocktail（混合的）of salts and minerals that supply industry, agriculture in water spa treatments and water therapies. The Dead Sea is located in the syro-African Rift, a 4000-mile fault line in the Earth’s crust. The lowest point of dry land on Earth is the shoreline of the Dead Sea at 1300 feet below sea level .Because the lake is at the lowest point ,this means that water does not drain from it . _____（49） Figures for the Dead Sea’s salinity（盐度）today range from 25% to 35%. But the greatest tourist attraction is the incredible city of Petra. _____（50） It is a vast unique city ,carved into the sheer rock face by the Nabataeans, an industrious Arab people who settled here more than 2000 years ago, turing it into an important junction for the silk, spice and other trade routes that linked China India and southern Arabia with Egypt ,Syria ,Greece and Rome .Today ,visitors can marvel at the architecture and explore life as it was thousands of years ago .

A:It is the largest wadi (riverbed) in Jordan. B:It is the second highest peak in Jordon ,rising directly above the Rum valley opposite Jebal Urn Ishrin. C:This vast stretch of water receives a number of incoming rivers, including the River Jordan. D:The area has been used as a backgroud setting in a number of films. E:Every day seven million tons of water evaporate from the lake ,but the mineral remain causing the salt content to increase . F:It is without doubt Jordan’s most valuable treasure.

Explore Jordan Wadi Rum is the name given to a valley cut into the sandstone and hard rock in southwest Jordan. _____（46） The name Rum most likely comes from an Aramaic word meaning “high” or “elevated”, The area around Wadi Rum is now also one of Jordan’s most important tourist destinations, and attracts an increasing number of foreign tourists, particularly trekkers（越野者），but also for camel safaris（旅行） or simply day-trippers from Aqaba or Petra. In contrast, there are almost no local or Arab tourists through Popular activities in the desert environment include camping under the stars ,riding Arab horses ,and rock-climbing amongst the massive rock formations .Jebal Rum(Jebal means mountain )is 1574 metres above sea level. _____（47）. But Jordan is not simply a desert environment ——it also contains the area which is the lowest point to the face of the Earth ——the incredible Dead Sea, popular with tourists for swimming. _____（48） Once the waters reach the Dead Sea they are landlocked and have nowhere to go, so they evaporate ,leaving behind a dense ,rich cocktail（混合的）of salts and minerals that supply industry, agriculture in water spa treatments and water therapies. The Dead Sea is located in the syro-African Rift, a 4000-mile fault line in the Earth’s crust. The lowest point of dry land on Earth is the shoreline of the Dead Sea at 1300 feet below sea level .Because the lake is at the lowest point ,this means that water does not drain from it . _____（49） Figures for the Dead Sea’s salinity（盐度）today range from 25% to 35%. But the greatest tourist attraction is the incredible city of Petra. _____（50） It is a vast unique city ,carved into the sheer rock face by the Nabataeans, an industrious Arab people who settled here more than 2000 years ago, turing it into an important junction for the silk, spice and other trade routes that linked China India and southern Arabia with Egypt ,Syria ,Greece and Rome .Today ,visitors can marvel at the architecture and explore life as it was thousands of years ago .

A:It is the largest wadi (riverbed) in Jordan. B:It is the second highest peak in Jordon ,rising directly above the Rum valley opposite Jebal Urn Ishrin. C:This vast stretch of water receives a number of incoming rivers, including the River Jordan. D:The area has been used as a backgroud setting in a number of films. E:Every day seven million tons of water evaporate from the lake ,but the mineral remain causing the salt content to increase . F:It is without doubt Jordan’s most valuable treasure.

Explore Jordan Wadi Rum is the name given to a valley cut into the sandstone and hard rock in southwest Jordan. _____（46）The name Rum most likely comes from an Aramaic word meaning "high" or "elevated", The area around Wadi Rum is now also one of Jordan’s most important tourist destinations, and attracts an increasing number of foreign tourists, particularly trekkers（越野者），but also for camel safaris（旅行）or simply day-trippers from Aqaba or Petra. In contrast, there are almost no local or Arab tourists, through Disi attracts young people from Amman at the weekends. Popular activities in the desert environment include camping under the stars, riding Arab horses, and rock-climbing amongst the massive rock formations .Jebal Rum （Jebal means "mountain"） is 1,574 metres above sea level. _____（47）. But Jordan is not simply a desert environment—it also contains the area which is the lowest point to the face of the Earth—the incredible Dead Sea, popular with tourists for swimming. _____（48）Once the waters reach the Dead Sea they are landlocked and have nowhere to go, so they evaporate ,leaving behind a dense ,rich cocktail（混合的）of salts and minerals that supply industry, agriculture and medicine with some of its finest products. Once again, tourists benefit and can participate in water spa treatments and water therapies. The Dead Sea is located in the Syro-African Rift, a 4,000-mile fault line in the Earth’s crust. The lowest point of dry land on Earth is the shoreline of the Dead Sea at 1,300 feet below sea level .Because the lake is at the lowest point, this means that water does not drain from it. _____（49）Figures for the Dead Sea’s salinity（盐度）today range from 25% to 35%. But the greatest tourist attraction is the incredible city of Petra. _____（50）It is a vast, unique city, carved into the sheer rock face by the Nabataeans, an industrious Arab people who settled here more than 2,000 years ago, turning it into an important junction for the silk, spice and other trade routes that linked China India and southern Arabia with Egypt, Syria, Greece and Rome. Today, visitors can marvel at the architecture and explore life as it was thousands of years ago.

A:It is the second highest peak in Jordan, rising directly above the Rum valley opposite Jebal Urn Ishrin. B:This vast stretch of water receives a number of incoming rivers, including the River Jordan. C:The area has been used as a background setting in a number of films. D:It is the largest wadi (riverbed) in Jordan. E:Every day seven million tons of water evaporate from the lake, but the minerals remain, causing the salt content to increase. F:It is without doubt Jordan’s most valuable treasure.

Explore Jordan Wadi Rum is the name given to a valley cut into the sandstone and hard rock in southwest Jordan. _____（46）The name Rum most likely comes from an Aramaic word meaning "high" or "elevated", The area around Wadi Rum is now also one of Jordan’s most important tourist destinations, and attracts an increasing number of foreign tourists, particularly trekkers（越野者），but also for camel safaris（旅行）or simply day-trippers from Aqaba or Petra. In contrast, there are almost no local or Arab tourists, through Disi attracts young people from Amman at the weekends. Popular activities in the desert environment include camping under the stars, riding Arab horses, and rock-climbing amongst the massive rock formations .Jebal Rum （Jebal means "mountain"） is 1,574 metres above sea level. _____（47）. But Jordan is not simply a desert environment—it also contains the area which is the lowest point to the face of the Earth—the incredible Dead Sea, popular with tourists for swimming. _____（48）Once the waters reach the Dead Sea they are landlocked and have nowhere to go, so they evaporate ,leaving behind a dense ,rich cocktail（混合的）of salts and minerals that supply industry, agriculture and medicine with some of its finest products. Once again, tourists benefit and can participate in water spa treatments and water therapies. The Dead Sea is located in the Syro-African Rift, a 4,000-mile fault line in the Earth’s crust. The lowest point of dry land on Earth is the shoreline of the Dead Sea at 1,300 feet below sea level .Because the lake is at the lowest point, this means that water does not drain from it. _____（49）Figures for the Dead Sea’s salinity（盐度）today range from 25% to 35%. But the greatest tourist attraction is the incredible city of Petra. _____（50）It is a vast, unique city, carved into the sheer rock face by the Nabataeans, an industrious Arab people who settled here more than 2,000 years ago, turning it into an important junction for the silk, spice and other trade routes that linked China India and southern Arabia with Egypt, Syria, Greece and Rome. Today, visitors can marvel at the architecture and explore life as it was thousands of years ago.

A:It is the second highest peak in Jordan, rising directly above the Rum valley opposite Jebal Urn Ishrin. B:This vast stretch of water receives a number of incoming rivers, including the River Jordan. C:The area has been used as a background setting in a number of films. D:It is the largest wadi (riverbed) in Jordan. E:Every day seven million tons of water evaporate from the lake, but the minerals remain, causing the salt content to increase. F:It is without doubt Jordan’s most valuable treasure.

Explore Jordan Wadi Rum is the name given to a valley cut into the sandstone and hard rock in southwest Jordan. _____（46）The name Rum most likely comes from an Aramaic word meaning "high" or "elevated", The area around Wadi Rum is now also one of Jordan’s most important tourist destinations, and attracts an increasing number of foreign tourists, particularly trekkers（越野者），but also for camel safaris（旅行）or simply day-trippers from Aqaba or Petra. In contrast, there are almost no local or Arab tourists, through Disi attracts young people from Amman at the weekends. Popular activities in the desert environment include camping under the stars, riding Arab horses, and rock-climbing amongst the massive rock formations .Jebal Rum （Jebal means "mountain"） is 1,574 metres above sea level. _____（47）. But Jordan is not simply a desert environment—it also contains the area which is the lowest point to the face of the Earth—the incredible Dead Sea, popular with tourists for swimming. _____（48）Once the waters reach the Dead Sea they are landlocked and have nowhere to go, so they evaporate ,leaving behind a dense ,rich cocktail（混合的）of salts and minerals that supply industry, agriculture and medicine with some of its finest products. Once again, tourists benefit and can participate in water spa treatments and water therapies. The Dead Sea is located in the Syro-African Rift, a 4,000-mile fault line in the Earth’s crust. The lowest point of dry land on Earth is the shoreline of the Dead Sea at 1,300 feet below sea level .Because the lake is at the lowest point, this means that water does not drain from it. _____（49）Figures for the Dead Sea’s salinity（盐度）today range from 25% to 35%. But the greatest tourist attraction is the incredible city of Petra. _____（50）It is a vast, unique city, carved into the sheer rock face by the Nabataeans, an industrious Arab people who settled here more than 2,000 years ago, turning it into an important junction for the silk, spice and other trade routes that linked China India and southern Arabia with Egypt, Syria, Greece and Rome. Today, visitors can marvel at the architecture and explore life as it was thousands of years ago.

A:It is the second highest peak in Jordan, rising directly above the Rum valley opposite Jebal Urn Ishrin. B:This vast stretch of water receives a number of incoming rivers, including the River Jordan. C:The area has been used as a background setting in a number of films. D:It is the largest wadi (riverbed) in Jordan. E:Every day seven million tons of water evaporate from the lake, but the minerals remain, causing the salt content to increase. F:It is without doubt Jordan’s most valuable treasure.