Choose the word which has OPPOSITE meaning to the underlined word
A tableau is a stationary scene containing living or inanimate three-dimensional figures.
A.a mobile
B.an immense
C.an attractive
D.a dynamic

Read the following passage, and mark the letter (A, B, C or D) on your answer sheet to indicate the correct answer to each question.
 The first scientific attempt at coaxing moisture from a cloud was in 1946, when scientist Vincent Schaefer dropped 3 pounds of dry ice from an airplane into cloud and, to his delight, produced snow. The success of experiment was modest, but it spawned optimism among farmers and ranchers around the country. It seemed to them that science had finally triumphed over weather.
Unfortunately, it didn’t work out that way. Although there were many cloud- seeding operations during the late 1940s and the 1950s, no one could say whether they had any effect on precipitation. Cloud seeding, or weather modification as it came to be called, was clearly more complicated than had been thought. It was not until the early 1970s that enough experiments had been done to understand the processes involved. What these studies indicated was that only certain types of clouds are amenable to seeding. One of the most responsive is the winter orographic cloud, formed when air currents encounters mountain slope and rise. If the temperature in such a cloud is right, seeding can increase snow yield by 10 to 20 percent.
There are two major methods of weather modification. In one method, silver iodide is burned in propane- fired ground generators. The smoke rises into the clouds where the tiny silver iodide particles act as nuclei for the formation of ice crystals. The alternate system uses airplanes to deliver dry-ice pellets. Dry ice does not provide ice- forming nuclei. Instead, it lowers the temperature near the water droplets in the cloud so that they freeze instantly – a process called spontaneous nucleation. Seeding from aircraft is more efficient but also more expensive.
About 75 percent of all weather modification in the United States takes places in the Western states. With the population of the West growing rapidly, few regions of the world require more water. About 85 percent of the waters in the rivers of the West comes from melted snow. As one expert put it, the water problems of the future may make the energy problems of the 70s seem like child’s play to solve. That’s why the U.S. Bureau of Reclamation, along with state governments, municipal water districts, and private interests such as ski areas and agricultural cooperatives, is putting increased efforts into cloud- seeding efforts. Without consistent and heavy snowfalls in the Rockies and Sierras, the West’s disastrous snow drought of 1976-77. It is impossible to judge the efficiency of weather modification based on one crash program, but most experts think that such hurry- up programs are not very effective.
The author mentions agricultural cooperatives as an example of _____________.
A.organizations that compete with ski areas for water
B.state government agencies
C.private interests
D.municipal water districts

Read the following passage, and mark the letter (A, B, C or D) on your answer sheet to indicate the correct answer to each question.
 The first scientific attempt at coaxing moisture from a cloud was in 1946, when scientist Vincent Schaefer dropped 3 pounds of dry ice from an airplane into cloud and, to his delight, produced snow. The success of experiment was modest, but it spawned optimism among farmers and ranchers around the country. It seemed to them that science had finally triumphed over weather.
Unfortunately, it didn’t work out that way. Although there were many cloud- seeding operations during the late 1940s and the 1950s, no one could say whether they had any effect on precipitation. Cloud seeding, or weather modification as it came to be called, was clearly more complicated than had been thought. It was not until the early 1970s that enough experiments had been done to understand the processes involved. What these studies indicated was that only certain types of clouds are amenable to seeding. One of the most responsive is the winter orographic cloud, formed when air currents encounters mountain slope and rise. If the temperature in such a cloud is right, seeding can increase snow yield by 10 to 20 percent.
There are two major methods of weather modification. In one method, silver iodide is burned in propane- fired ground generators. The smoke rises into the clouds where the tiny silver iodide particles act as nuclei for the formation of ice crystals. The alternate system uses airplanes to deliver dry-ice pellets. Dry ice does not provide ice- forming nuclei. Instead, it lowers the temperature near the water droplets in the cloud so that they freeze instantly – a process called spontaneous nucleation. Seeding from aircraft is more efficient but also more expensive.
About 75 percent of all weather modification in the United States takes places in the Western states. With the population of the West growing rapidly, few regions of the world require more water. About 85 percent of the waters in the rivers of the West comes from melted snow. As one expert put it, the water problems of the future may make the energy problems of the 70s seem like child’s play to solve. That’s why the U.S. Bureau of Reclamation, along with state governments, municipal water districts, and private interests such as ski areas and agricultural cooperatives, is putting increased efforts into cloud- seeding efforts. Without consistent and heavy snowfalls in the Rockies and Sierras, the West’s disastrous snow drought of 1976-77. It is impossible to judge the efficiency of weather modification based on one crash program, but most experts think that such hurry- up programs are not very effective.
What does the author imply about the energy problems of the 1970s?
A.They may not be as critical as water problems will be in the future.
B.They took attention away from water problems
C.They were thought to be minor at the time but turned out to be serious.      
D.They were caused by a lack of water.

Read the following passage, and mark the letter (A, B, C or D) on your answer sheet to indicate the correct answer to each question.
 The first scientific attempt at coaxing moisture from a cloud was in 1946, when scientist Vincent Schaefer dropped 3 pounds of dry ice from an airplane into cloud and, to his delight, produced snow. The success of experiment was modest, but it spawned optimism among farmers and ranchers around the country. It seemed to them that science had finally triumphed over weather.
Unfortunately, it didn’t work out that way. Although there were many cloud- seeding operations during the late 1940s and the 1950s, no one could say whether they had any effect on precipitation. Cloud seeding, or weather modification as it came to be called, was clearly more complicated than had been thought. It was not until the early 1970s that enough experiments had been done to understand the processes involved. What these studies indicated was that only certain types of clouds are amenable to seeding. One of the most responsive is the winter orographic cloud, formed when air currents encounters mountain slope and rise. If the temperature in such a cloud is right, seeding can increase snow yield by 10 to 20 percent.
There are two major methods of weather modification. In one method, silver iodide is burned in propane- fired ground generators. The smoke rises into the clouds where the tiny silver iodide particles act as nuclei for the formation of ice crystals. The alternate system uses airplanes to deliver dry-ice pellets. Dry ice does not provide ice- forming nuclei. Instead, it lowers the temperature near the water droplets in the cloud so that they freeze instantly – a process called spontaneous nucleation. Seeding from aircraft is more efficient but also more expensive.
About 75 percent of all weather modification in the United States takes places in the Western states. With the population of the West growing rapidly, few regions of the world require more water. About 85 percent of the waters in the rivers of the West comes from melted snow. As one expert put it, the water problems of the future may make the energy problems of the 70s seem like child’s play to solve. That’s why the U.S. Bureau of Reclamation, along with state governments, municipal water districts, and private interests such as ski areas and agricultural cooperatives, is putting increased efforts into cloud- seeding efforts. Without consistent and heavy snowfalls in the Rockies and Sierras, the West’s disastrous snow drought of 1976-77. It is impossible to judge the efficiency of weather modification based on one crash program, but most experts think that such hurry- up programs are not very effective.
When clouds are seeded from the ground, what actually causes ice crystals to form?
A.silver- iodidixe smoke
B.nuclear radiation
C.dry- ice pellets          
D.propane

Read the following passage, and mark the letter (A, B, C or D) on your answer sheet to indicate the correct answer to each question.
 The first scientific attempt at coaxing moisture from a cloud was in 1946, when scientist Vincent Schaefer dropped 3 pounds of dry ice from an airplane into cloud and, to his delight, produced snow. The success of experiment was modest, but it spawned optimism among farmers and ranchers around the country. It seemed to them that science had finally triumphed over weather.
Unfortunately, it didn’t work out that way. Although there were many cloud- seeding operations during the late 1940s and the 1950s, no one could say whether they had any effect on precipitation. Cloud seeding, or weather modification as it came to be called, was clearly more complicated than had been thought. It was not until the early 1970s that enough experiments had been done to understand the processes involved. What these studies indicated was that only certain types of clouds are amenable to seeding. One of the most responsive is the winter orographic cloud, formed when air currents encounters mountain slope and rise. If the temperature in such a cloud is right, seeding can increase snow yield by 10 to 20 percent.
There are two major methods of weather modification. In one method, silver iodide is burned in propane- fired ground generators. The smoke rises into the clouds where the tiny silver iodide particles act as nuclei for the formation of ice crystals. The alternate system uses airplanes to deliver dry-ice pellets. Dry ice does not provide ice- forming nuclei. Instead, it lowers the temperature near the water droplets in the cloud so that they freeze instantly – a process called spontaneous nucleation. Seeding from aircraft is more efficient but also more expensive.
About 75 percent of all weather modification in the United States takes places in the Western states. With the population of the West growing rapidly, few regions of the world require more water. About 85 percent of the waters in the rivers of the West comes from melted snow. As one expert put it, the water problems of the future may make the energy problems of the 70s seem like child’s play to solve. That’s why the U.S. Bureau of Reclamation, along with state governments, municipal water districts, and private interests such as ski areas and agricultural cooperatives, is putting increased efforts into cloud- seeding efforts. Without consistent and heavy snowfalls in the Rockies and Sierras, the West’s disastrous snow drought of 1976-77. It is impossible to judge the efficiency of weather modification based on one crash program, but most experts think that such hurry- up programs are not very effective.
The pronoun “they” refers to _____________.
A.ice-forming nuclei
B.water droplets
C.airplanes
D.clouds

Read the following passage, and mark the letter (A, B, C or D) on your answer sheet to indicate the correct answer to each question.
 The first scientific attempt at coaxing moisture from a cloud was in 1946, when scientist Vincent Schaefer dropped 3 pounds of dry ice from an airplane into cloud and, to his delight, produced snow. The success of experiment was modest, but it spawned optimism among farmers and ranchers around the country. It seemed to them that science had finally triumphed over weather.
Unfortunately, it didn’t work out that way. Although there were many cloud- seeding operations during the late 1940s and the 1950s, no one could say whether they had any effect on precipitation. Cloud seeding, or weather modification as it came to be called, was clearly more complicated than had been thought. It was not until the early 1970s that enough experiments had been done to understand the processes involved. What these studies indicated was that only certain types of clouds are amenable to seeding. One of the most responsive is the winter orographic cloud, formed when air currents encounters mountain slope and rise. If the temperature in such a cloud is right, seeding can increase snow yield by 10 to 20 percent.
There are two major methods of weather modification. In one method, silver iodide is burned in propane- fired ground generators. The smoke rises into the clouds where the tiny silver iodide particles act as nuclei for the formation of ice crystals. The alternate system uses airplanes to deliver dry-ice pellets. Dry ice does not provide ice- forming nuclei. Instead, it lowers the temperature near the water droplets in the cloud so that they freeze instantly – a process called spontaneous nucleation. Seeding from aircraft is more efficient but also more expensive.
About 75 percent of all weather modification in the United States takes places in the Western states. With the population of the West growing rapidly, few regions of the world require more water. About 85 percent of the waters in the rivers of the West comes from melted snow. As one expert put it, the water problems of the future may make the energy problems of the 70s seem like child’s play to solve. That’s why the U.S. Bureau of Reclamation, along with state governments, municipal water districts, and private interests such as ski areas and agricultural cooperatives, is putting increased efforts into cloud- seeding efforts. Without consistent and heavy snowfalls in the Rockies and Sierras, the West’s disastrous snow drought of 1976-77. It is impossible to judge the efficiency of weather modification based on one crash program, but most experts think that such hurry- up programs are not very effective.
According to the passage, winter orographic clouds are formed ____________.
A.during intense snow storms
B.when air currents rise over mountains
C.over large bodies of water
D.on relatively warm winter days

Read the following passage, and mark the letter (A, B, C or D) on your answer sheet to indicate the correct answer to each question.
 The first scientific attempt at coaxing moisture from a cloud was in 1946, when scientist Vincent Schaefer dropped 3 pounds of dry ice from an airplane into cloud and, to his delight, produced snow. The success of experiment was modest, but it spawned optimism among farmers and ranchers around the country. It seemed to them that science had finally triumphed over weather.
Unfortunately, it didn’t work out that way. Although there were many cloud- seeding operations during the late 1940s and the 1950s, no one could say whether they had any effect on precipitation. Cloud seeding, or weather modification as it came to be called, was clearly more complicated than had been thought. It was not until the early 1970s that enough experiments had been done to understand the processes involved. What these studies indicated was that only certain types of clouds are amenable to seeding. One of the most responsive is the winter orographic cloud, formed when air currents encounters mountain slope and rise. If the temperature in such a cloud is right, seeding can increase snow yield by 10 to 20 percent.
There are two major methods of weather modification. In one method, silver iodide is burned in propane- fired ground generators. The smoke rises into the clouds where the tiny silver iodide particles act as nuclei for the formation of ice crystals. The alternate system uses airplanes to deliver dry-ice pellets. Dry ice does not provide ice- forming nuclei. Instead, it lowers the temperature near the water droplets in the cloud so that they freeze instantly – a process called spontaneous nucleation. Seeding from aircraft is more efficient but also more expensive.
About 75 percent of all weather modification in the United States takes places in the Western states. With the population of the West growing rapidly, few regions of the world require more water. About 85 percent of the waters in the rivers of the West comes from melted snow. As one expert put it, the water problems of the future may make the energy problems of the 70s seem like child’s play to solve. That’s why the U.S. Bureau of Reclamation, along with state governments, municipal water districts, and private interests such as ski areas and agricultural cooperatives, is putting increased efforts into cloud- seeding efforts. Without consistent and heavy snowfalls in the Rockies and Sierras, the West’s disastrous snow drought of 1976-77. It is impossible to judge the efficiency of weather modification based on one crash program, but most experts think that such hurry- up programs are not very effective.
Which of the following can be inferred from the passage about the term “weather modification”?
A.It was first used by Vincent Schaefer.
B.It refers to only one type of cloud seeding.
C.It is not as old as the term cloud seeding.
D.It has been in use since at least 1946.

Read the following passage, and mark the letter (A, B, C or D) on your answer sheet to indicate the correct answer to each question.
 The first scientific attempt at coaxing moisture from a cloud was in 1946, when scientist Vincent Schaefer dropped 3 pounds of dry ice from an airplane into cloud and, to his delight, produced snow. The success of experiment was modest, but it spawned optimism among farmers and ranchers around the country. It seemed to them that science had finally triumphed over weather.
Unfortunately, it didn’t work out that way. Although there were many cloud- seeding operations during the late 1940s and the 1950s, no one could say whether they had any effect on precipitation. Cloud seeding, or weather modification as it came to be called, was clearly more complicated than had been thought. It was not until the early 1970s that enough experiments had been done to understand the processes involved. What these studies indicated was that only certain types of clouds are amenable to seeding. One of the most responsive is the winter orographic cloud, formed when air currents encounters mountain slope and rise. If the temperature in such a cloud is right, seeding can increase snow yield by 10 to 20 percent.
There are two major methods of weather modification. In one method, silver iodide is burned in propane- fired ground generators. The smoke rises into the clouds where the tiny silver iodide particles act as nuclei for the formation of ice crystals. The alternate system uses airplanes to deliver dry-ice pellets. Dry ice does not provide ice- forming nuclei. Instead, it lowers the temperature near the water droplets in the cloud so that they freeze instantly – a process called spontaneous nucleation. Seeding from aircraft is more efficient but also more expensive.
About 75 percent of all weather modification in the United States takes places in the Western states. With the population of the West growing rapidly, few regions of the world require more water. About 85 percent of the waters in the rivers of the West comes from melted snow. As one expert put it, the water problems of the future may make the energy problems of the 70s seem like child’s play to solve. That’s why the U.S. Bureau of Reclamation, along with state governments, municipal water districts, and private interests such as ski areas and agricultural cooperatives, is putting increased efforts into cloud- seeding efforts. Without consistent and heavy snowfalls in the Rockies and Sierras, the West’s disastrous snow drought of 1976-77. It is impossible to judge the efficiency of weather modification based on one crash program, but most experts think that such hurry- up programs are not very effective.
After the cloud seeding operations of the late 1940s and the 1950s, the farmers and ranchers mentioned in the first paragraph probably felt ______________.
A.optimistic
B.disappointed
C.modest
D.triumphant

Read the following passage, and mark the letter (A, B, C or D) on your answer sheet to indicate the correct answer to each question.
 The first scientific attempt at coaxing moisture from a cloud was in 1946, when scientist Vincent Schaefer dropped 3 pounds of dry ice from an airplane into cloud and, to his delight, produced snow. The success of experiment was modest, but it spawned optimism among farmers and ranchers around the country. It seemed to them that science had finally triumphed over weather.
Unfortunately, it didn’t work out that way. Although there were many cloud- seeding operations during the late 1940s and the 1950s, no one could say whether they had any effect on precipitation. Cloud seeding, or weather modification as it came to be called, was clearly more complicated than had been thought. It was not until the early 1970s that enough experiments had been done to understand the processes involved. What these studies indicated was that only certain types of clouds are amenable to seeding. One of the most responsive is the winter orographic cloud, formed when air currents encounters mountain slope and rise. If the temperature in such a cloud is right, seeding can increase snow yield by 10 to 20 percent.
There are two major methods of weather modification. In one method, silver iodide is burned in propane- fired ground generators. The smoke rises into the clouds where the tiny silver iodide particles act as nuclei for the formation of ice crystals. The alternate system uses airplanes to deliver dry-ice pellets. Dry ice does not provide ice- forming nuclei. Instead, it lowers the temperature near the water droplets in the cloud so that they freeze instantly – a process called spontaneous nucleation. Seeding from aircraft is more efficient but also more expensive.
About 75 percent of all weather modification in the United States takes places in the Western states. With the population of the West growing rapidly, few regions of the world require more water. About 85 percent of the waters in the rivers of the West comes from melted snow. As one expert put it, the water problems of the future may make the energy problems of the 70s seem like child’s play to solve. That’s why the U.S. Bureau of Reclamation, along with state governments, municipal water districts, and private interests such as ski areas and agricultural cooperatives, is putting increased efforts into cloud- seeding efforts. Without consistent and heavy snowfalls in the Rockies and Sierras, the West’s disastrous snow drought of 1976-77. It is impossible to judge the efficiency of weather modification based on one crash program, but most experts think that such hurry- up programs are not very effective.
The word “spawned” is closest in meaning to ______________.
A.intensified
B.preceded
C.created
D.reduced

Read the following passage, and mark the letter (A, B, C or D) on your answer sheet to indicate the correct answer to each question.
 The first scientific attempt at coaxing moisture from a cloud was in 1946, when scientist Vincent Schaefer dropped 3 pounds of dry ice from an airplane into cloud and, to his delight, produced snow. The success of experiment was modest, but it spawned optimism among farmers and ranchers around the country. It seemed to them that science had finally triumphed over weather.
Unfortunately, it didn’t work out that way. Although there were many cloud- seeding operations during the late 1940s and the 1950s, no one could say whether they had any effect on precipitation. Cloud seeding, or weather modification as it came to be called, was clearly more complicated than had been thought. It was not until the early 1970s that enough experiments had been done to understand the processes involved. What these studies indicated was that only certain types of clouds are amenable to seeding. One of the most responsive is the winter orographic cloud, formed when air currents encounters mountain slope and rise. If the temperature in such a cloud is right, seeding can increase snow yield by 10 to 20 percent.
There are two major methods of weather modification. In one method, silver iodide is burned in propane- fired ground generators. The smoke rises into the clouds where the tiny silver iodide particles act as nuclei for the formation of ice crystals. The alternate system uses airplanes to deliver dry-ice pellets. Dry ice does not provide ice- forming nuclei. Instead, it lowers the temperature near the water droplets in the cloud so that they freeze instantly – a process called spontaneous nucleation. Seeding from aircraft is more efficient but also more expensive.
About 75 percent of all weather modification in the United States takes places in the Western states. With the population of the West growing rapidly, few regions of the world require more water. About 85 percent of the waters in the rivers of the West comes from melted snow. As one expert put it, the water problems of the future may make the energy problems of the 70s seem like child’s play to solve. That’s why the U.S. Bureau of Reclamation, along with state governments, municipal water districts, and private interests such as ski areas and agricultural cooperatives, is putting increased efforts into cloud- seeding efforts. Without consistent and heavy snowfalls in the Rockies and Sierras, the West’s disastrous snow drought of 1976-77. It is impossible to judge the efficiency of weather modification based on one crash program, but most experts think that such hurry- up programs are not very effective.
What is the main subject of the passage?
A.The effects of cloud seeding
B.The process by which snow crystals form
C.Developments in methods of increasing precipitation
D.The scientific contributions of Vincent Schaefer