The Inventor of LEDWhen Nick Holonyak set out to create a new kind of visible lighting using semiconductor（半导体）alloys（合金），his colleagues thought he was unrealistic. Today，his discovery of light-emitting diodes，or LEDs，is used in everything from DVDs to alarm clocks to airports. Dozens of his students have continued his work，developing lighting used in traffic lights and other everyday technology.On April 23，2004，Holonyak received the $500,000 Lemelson-MIT Prize at a ceremony in Washington. This marks the 10th vear that the Lemelson-MIT Program at the Massachusetts Institute of Technology（MIT）has given the award to prominent inventors."Anytime you get an award，big or little，it's always a surprise，"Holonyak said.Holonyak，75，was a student of John Bardeen，an inventor of the transistor（晶体管），in the early 1950s.After graduate school，Holonyak worked at Bell Labs. He later went to General Electric，where he invented a switch now widely used in house dimmer switches. Later，Holonyak started looking into how semiconductors could be used to generate light. But while his colleagues were looking into how to generate invisible light，he wanted to generate visible light. The LEDs he invented in 1962 now last about 10 times longer than incandescent bulbs，and are more environmentally friendly and cost effective.Holonyak，now a professor of electrical and computer engineering and physics at the University of Illinois，said he suspected that LEDs would become as commonplace（平凡的）as they are today，but didn't realize how many uses they would have."You don't know in the beginning. You think you're doing something important，you think it’s worth doing，but you really can't tell what the big payoff（成果）is going to be，and when，and how. You just don't know. “he said.The Lemelson-MIT Program also recognized Edith Flanigen，75，with the $100,000 Lemelson-MIT Lifetime Achievement Award for the work on a new generation of "molecular（分子）sieves（滤网）"that can separate molecules by size.【第10题】The Lemelson-MIT Prize has a history of over 100 years.

Skyscrapers and EnvironmentIn the late 1960's，many people in North America turned their attention to environmental problems，and new steel-and-glass skyscrapers were widely criticized. Ecologists pointed out that a cluster of tall buildings in a city often overburdens public transportation and parking lot capacities.Skyscrapers are also lavish consumers，and wasters，of electric power. In one recent year，the addition of 17 million square feet of skyscraper office space in New York City raised the peak daily demand for electricity by 120，000 kilowatts-enough to supply the entire city of Albany，New York，for a day.Glass-walled skyscrapers can be especially wasteful. The heat loss（or gain）through a wall of half-inch plate glass is more than ten times that through a typical masonry wall（砌筑墙）filled with insulation board（隔热板）.To lessen the strain on heating and air-conditioning equipment，builders of skyscrapers have begun to use double-glazed panels of glass，and reflective glasses coated with silver or gold mirror films that reduce glare as well as heat gain. However，mirror-walled skyscrapers raise the temperature of the surrounding air and affect neighboring buildings.Skyscrapers put a severe strain on a city's sanitation facilities，too.If fully occeupied，the two World Trade Center towers in New York City would alone generate 2.25 million gallons of raw sewage each year-as much as a city the size of Stanford，Connecticut，which has a population of more than 109，000.【第11题】11.The main purpose of the passage is to_____.

Skyscrapers and EnvironmentIn the late 1960's，many people in North America turned their attention to environmental problems，and new steel-and-glass skyscrapers were widely criticized. Ecologists pointed out that a cluster of tall buildings in a city often overburdens public transportation and parking lot capacities.Skyscrapers are also lavish consumers，and wasters，of electric power. In one recent year，the addition of 17 million square feet of skyscraper office space in New York City raised the peak daily demand for electricity by 120，000 kilowatts-enough to supply the entire city of Albany，New York，for a day.Class-walled skyscrapers can be especially wasteful. The heat loss（or gain）through a wall of half-inch plate glass is more than ten times that through a typical masonry wall（砌筑墙）filled with insulation board（隔热板）.To lessen the strain on heating and air-conditioning equipment，builders of skyscrapers have begun to use double-glazed panels of glass，and reflective glasses coated with silver or gold mirror films that reduce glare as well as heat gain. However，mirror-walled skyscrapers raise the temperature of the surrounding air and affect neighboring buildings.Skyscrapers put a severe strain on a city's sanitation facilities，too.If fully occeupied，the two World Trade Center towers in New York City would alone generate 2.25 million gallons of raw sewage each year-as much as a city the size of Stanford，Connecticut，which has a population of more than 109，000.【第12题】 According to the passage, what is one disadvantage of skyscrapers that have mirrored walls?

Skyscrapers and EnvironmentIn the late 1960's，many people in North America turned their attention to environmental problems，and new steel-and-glass skyscrapers were widely criticized. Ecologists pointed out that a cluster of tall buildings in a city often overburdens public transportation and parking lot capacities.Skyscrapers are also lavish consumers，and wasters，of electric power. In one recent year，the addition of 17 million square feet of skyscraper office space in New York City raised the peak daily demand for electricity by 120，000 kilowatts-enough to supply the entire city of Albany，New York，for a day.Class-walled skyscrapers can be especially wasteful. The heat loss（or gain）through a wall of half-inch plate glass is more than ten times that through a typical masonry wall（砌筑墙）filled with insulation board（隔热板）.To lessen the strain on heating and air-conditioning equipment，builders of skyscrapers have begun to use double-glazed panels of glass，and reflective glasses coated with silver or gold mirror films that reduce glare as well as heat gain. However，mirror-walled skyscrapers raise the temperature of the surrounding air and affect neighboring buildings.Skyscrapers put a severe strain on a city's sanitation facilities，too.If fully occeupied，the two World Trade Center towers in New York City would alone generate 2.25 million gallons of raw sewage each year-as much as a city the size of Stanford，Connecticut，which has a population of more than 109，000.【第13题】According to the passage,which aspect of skyscrapers were some residents of North America concerned with in the late 1960's?

Skyscrapers and EnvironmentIn the late 1960's，many people in North America turned their attention to environmental problems，and new steel-and-glass skyscrapers were widely criticized. Ecologists pointed out that a cluster of tall buildings in a city often overburdens public transportation and parking lot capacities.Skyscrapers are also lavish consumers，and wasters，of electric power. In one recent year，the addition of 17 million square feet of skyscraper office space in New York City raised the peak daily demand for electricity by 120，000 kilowatts-enough to supply the entire city of Albany，New York，for a day.Class-walled skyscrapers can be especially wasteful. The heat loss（or gain）through a wall of half-inch plate glass is more than ten times that through a typical masonry wall（砌筑墙）filled with insulation board（隔热板）.To lessen the strain on heating and air-conditioning equipment，builders of skyscrapers have begun to use double-glazed panels of glass，and reflective glasses coated with silver or gold mirror films that reduce glare as well as heat gain. However，mirror-walled skyscrapers raise the temperature of the surrounding air and affect neighboring buildings.Skyscrapers put a severe strain on a city's sanitation facilities，too.If fully occeupied，the two World Trade Center towers in New York City would alone generate 2.25 million gallons of raw sewage each year-as much as a city the size of Stanford，Connecticut，which has a population of more than 109，000.【第14题】Which of the following groups would the skyscraper issue most concern?

Skyscrapers and EnvironmentIn the late 1960's，many people in North America turned their attention to environmental problems，and new steel-and-glass skyscrapers were widely criticized. Ecologists pointed out that a cluster of tall buildings in a city often overburdens public transportation and parking lot capacities.Skyscrapers are also lavish consumers，and wasters，of electric power. In one recent year，the addition of 17 million square feet of skyscraper office space in New York City raised the peak daily demand for electricity by 120，000 kilowatts-enough to supply the entire city of Albany，New York，for a day.Class-walled skyscrapers can be especially wasteful. The heat loss（or gain）through a wall of half-inch plate glass is more than ten times that through a typical masonry wall（砌筑墙）filled with insulation board（隔热板）.To lessen the strain on heating and air-conditioning equipment，builders of skyscrapers have begun to use double-glazed panels of glass，and reflective glasses coated with silver or gold mirror films that reduce glare as well as heat gain. However，mirror-walled skyscrapers raise the temperature of the surrounding air and affect neighboring buildings.S②xorld Trade Center towers in New York City would alone generate 2.25 million gallons of raw sewage each year-as much as a city the size of Stanford，Connecticut，which has a population of more than 109，000.【第15题】Which of the following is true according to the passage?

Alaska① In 1858 Americans welcomed Alaska into the Union as the 49th state, symbolizing a change of attitude that hold in 1867 , when the peninsula was purchased from Russia. Then, most Americans had little interest in 1,500,000 square kilometers "of icebergs and polar bear"-beyond Canada's western borders, far from the settled areas of the United States.②In those sections of the state which lie above the Arctic Circle, Alaska still is a land of icebergs and polar bear. Ice buried in the earth, which is permanently frozen to a depth of 90 or more meters, From early May until early August, the midnight sun never sets on this flat, treeless region, but the sun cannot melt the icy soil more than two thirds of a meter down.③Alaska is America's largest slate, but only about 325 ,000 people live there. According to estimates, 800, 000 hectares of its land area are fit for plowing but only about 640,000 hectares are being cultivated.④Arctic Alaska has been the home of Eskimos for countless centuries. It is believed that the Eskimos moved there from Mongolia or Siberia, probably crossing Bering Strait, named for Vitus Bering, the Danish sea captain who discovered Alaska on his voyage for Russia in 1741. The Eskimos are the state’s earliest known inhabitants. Russian fur traders established settlements but, by the time Alaska was sold to the United States, most of the traders had departed.⑤In 1896 gold was discovered near the Klondike River in Canada just across the Alaskan border. Thousands of Americans rushed to the region on their way to Klondike; Alaska was never completely cut off again, although even today transportation is a major problem. There are only two motor routes from the U. S. mainland, and within the state, every town has its own airfield. Planes fly passengers, mail and freight to the most distant villages.The gold that changed life so suddenly for Alaska wassoon ended, and although many stories about mining camps have become part of American literature, the gold from Alaskan earth contributed less to economic progress than the fish from Alaska waters. The fish caught in a single year range in value from $80 million to $90 million. Fur-bearing animals are plentiful in the forests and streams, and valuable fur seals inhabit the waters. After fishing, the state's chief industry is lumber and the production of wood pulp. In recent years, Alaska' s single most important resource has become oil. The state also has large deposits of coal, copper , gold and other minerals.【第16题】Paragraph①____.A. Rich Resources of the State;B. Connections With the Outside World;C. Transportation Problem;D. The Natives of the Land;E. Position and Cold Climate;F. Land and Population

Alaska① In 1858 Americans welcomed Alaska into the Union as the 49th state, symbolizing a change of attitude that hold in 1867 , when the peninsula was purchased from Russia. Then, most Americans had little interest in 1,500,000 square kilometers "of icebergs and polar bear"-beyond Canada's western borders, far from the settled areas of the United States.②In those sections of the state which lie above the Arctic Circle, Alaska still is a land of icebergs and polar bear. Ice buried in the earth, which is permanently frozen to a depth of 90 or more meters, From early May until early August, the midnight sun never sets on this flat, treeless region, but the sun cannot melt the icy soil more than two thirds of a meter down.③Alaska is America's largest slate, but only about 325 ,000 people live there. According to estimates, 800, 000 hectares of its land area are fit for plowing but only about 640,000 hectares are being cultivated.④Arctic Alaska has been the home of Eskimos for countless centuries. It is believed that the Eskimos moved there from Mongolia or Siberia, probably crossing Bering Strait, named for Vitus Bering, the Danish sea captain who discovered Alaska on his voyage for Russia in 1741. The Eskimos are the state’s earliest known inhabitants. Russian fur traders established settlements but, by the time Alaska was sold to the United States, most of the traders had departed.⑤In 1896 gold was discovered near the Klondike River in Canada just across the Alaskan border. Thousands of Americans rushed to the region on their way to Klondike; Alaska was never completely cut off again, although even today transportation is a major problem. There are only two motor routes from the U. S. mainland, and within the state, every town has its own airfield. Planes fly passengers, mail and freight to the most distant villages.The gold that changed life so suddenly for Alaska wassoon ended, and although many stories about mining camps have become part of American literature, the gold from Alaskan earth contributed less to economic progress than the fish from Alaska waters. The fish caught in a single year range in value from $80 million to $90 million. Fur-bearing animals are plentiful in the forests and streams, and valuable fur seals inhabit the waters. After fishing, the state's chief industry is lumber and the production of wood pulp. In recent years, Alaska' s single most important resource has become oil. The state also has large deposits of coal, copper , gold and other minerals.【第17题】Paragraph②____.A. Rich Resources of the State;B. Connections With the Outside World;C. Transportation Problem;D. The Natives of the Land;E. Position and Cold Climate;F. Land and Population

Alaska① In 1858 Americans welcomed Alaska into the Union as the 49th state, symbolizing a change of attitude that hold in 1867 , when the peninsula was purchased from Russia. Then, most Americans had little interest in 1,500,000 square kilometers "of icebergs and polar bear"-beyond Canada's western borders, far from the settled areas of the United States.②In those sections of the state which lie above the Arctic Circle, Alaska still is a land of icebergs and polar bear. Ice buried in the earth, which is permanently frozen to a depth of 90 or more meters, From early May until early August, the midnight sun never sets on this flat, treeless region, but the sun cannot melt the icy soil more than two thirds of a meter down.③Alaska is America's largest slate, but only about 325 ,000 people live there. According to estimates, 800, 000 hectares of its land area are fit for plowing but only about 640,000 hectares are being cultivated.④Arctic Alaska has been the home of Eskimos for countless centuries. It is believed that the Eskimos moved there from Mongolia or Siberia, probably crossing Bering Strait, named for Vitus Bering, the Danish sea captain who discovered Alaska on his voyage for Russia in 1741. The Eskimos are the state’s earliest known inhabitants. Russian fur traders established settlements but, by the time Alaska was sold to the United States, most of the traders had departed.⑤In 1896 gold was discovered near the Klondike River in Canada just across the Alaskan border. Thousands of Americans rushed to the region on their way to Klondike; Alaska was never completely cut off again, although even today transportation is a major problem. There are only two motor routes from the U. S. mainland, and within the state, every town has its own airfield. Planes fly passengers, mail and freight to the most distant villages.The gold that changed life so suddenly for Alaska wassoon ended, and although many stories about mining camps have become part of American literature, the gold from Alaskan earth contributed less to economic progress than the fish from Alaska waters. The fish caught in a single year range in value from $80 million to $90 million. Fur-bearing animals are plentiful in the forests and streams, and valuable fur seals inhabit the waters. After fishing, the state's chief industry is lumber and the production of wood pulp. In recent years, Alaska' s single most important resource has become oil. The state also has large deposits of coal, copper , gold and other minerals.【第18题】Paragraph③____.A. Rich Resources of the State;B. Connections With the Outside World;C. Transportation Problem;D. The Natives of the Land;E. Position and Cold Climate;F. Land and Population

Alaska① In 1858 Americans welcomed Alaska into the Union as the 49th state, symbolizing a change of attitude that hold in 1867 , when the peninsula was purchased from Russia. Then, most Americans had little interest in 1,500,000 square kilometers "of icebergs and polar bear"-beyond Canada's western borders, far from the settled areas of the United States.②In those sections of the state which lie above the Arctic Circle, Alaska still is a land of icebergs and polar bear. Ice buried in the earth, which is permanently frozen to a depth of 90 or more meters, From early May until early August, the midnight sun never sets on this flat, treeless region, but the sun cannot melt the icy soil more than two thirds of a meter down.③Alaska is America's largest slate, but only about 325 ,000 people live there. According to estimates, 800, 000 hectares of its land area are fit for plowing but only about 640,000 hectares are being cultivated.④Arctic Alaska has been the home of Eskimos for countless centuries. It is believed that the Eskimos moved there from Mongolia or Siberia, probably crossing Bering Strait, named for Vitus Bering, the Danish sea captain who discovered Alaska on his voyage for Russia in 1741. The Eskimos are the state’s earliest known inhabitants. Russian fur traders established settlements but, by the time Alaska was sold to the United States, most of the traders had departed.⑤In 1896 gold was discovered near the Klondike River in Canada just across the Alaskan border. Thousands of Americans rushed to the region on their way to Klondike; Alaska was never completely cut off again, although even today transportation is a major problem. There are only two motor routes from the U. S. mainland, and within the state, every town has its own airfield. Planes fly passengers, mail and freight to the most distant villages.The gold that changed life so suddenly for Alaska wassoon ended, and although many stories about mining camps have become part of American literature, the gold from Alaskan earth contributed less to economic progress than the fish from Alaska waters. The fish caught in a single year range in value from $80 million to $90 million. Fur-bearing animals are plentiful in the forests and streams, and valuable fur seals inhabit the waters. After fishing, the state's chief industry is lumber and the production of wood pulp. In recent years, Alaska' s single most important resource has become oil. The state also has large deposits of coal, copper , gold and other minerals.【第19题】Paragraph④____.A. Rich Resources of the State;B. Connections With the Outside World;C. Transportation Problem;D. The Natives of the Land;E. Position and Cold Climate;F. Land and Population