Over the past l00 years，humankind has designed networks of canals，dams and reservoirs so extensive that the resulting redistribution of freshwater from one place to another and from one season to the next accounts for a srmll but measurable change in the wobble of the earth as it spins．①The statistics are staggerin9．Before l900 0nly 40 reservoirs had been built with storage volumes greater than 25 billion gallons； today almost 3，000 reservoirs larger than this inundate l 20 million acres of land and hold more than l，500 cubic miles of wateras much as Lake Michigan and Lake Ontario combined．。The more than 70，000 dams in the U s．a(chǎn)re capable of capturing and storing half of the annual river flow of the entire country．
In many nations，big dams and reservoirs were originally considered vital for national security， economic prosperity and agricultural survival．Until the late l970s and early l980s，few people took into account the environmental consequences of these massive projects．Today，however，the results are clear：dams have destroyed the ecosystems in and around countless rivers，lakes and streams．On the C01umbia and Snake rivers in the northwestern U．S．，95 percent of the juvenile salmon trying to reach the ocean do not survive passage through the numerous dams and reservoirs that block their way．More than 900 dams on New England and European rivers block Atlantic salmon from their spawning grounds， and their populations have falien to leSS than l percent of historical levels．
As environmental awareness has heightened globally，the desire to protect--and even restore--some of these natural resources has grown．The earliest environmental advocacy groups in the U．S．mobilized against dams proposed in places such as Yosemite National Park in California and the Grand Canyon in Arizona．In the l970s plans in the former Soviet Union to divert the flow of Siberian rivers away from the Arctic stimulated an unprecedented public outcry，helping to halt the projects．④In many developing countries，grassroots opposition to the environmental and social COSTS of big water projects is becoming more and more effective．Villagers and community activists in India have encouraged a public debate over major dams．
Until very recently．international financial organizations such as the World Bank，export-import banks and muhilateral aid agencies subsidized or paid in full for dams or other water-related civil engineering projects--which often have price tags in the tens of billions of dollars．These organizations are slowly beginning to reduce or eliminate such subsidies，putting more of the financial burden on already strained national economies．Having seen so much ineffective development in the past--and having borne the associated cOstS(both monetary and otherwise)of that development--many governments are unwilling to pay for new structures to solve water shortages and other problems．
A handful of countries are even taking steps to remove some of the most egregious and damaging dams．Altogether around 500 0ld，dangerous or environmentally harmful dams have been removed from U．S．rivers in the past few years．
Fortunately--and unexpectedly--the demand for water is not rising as rapidly as some predicted．As a result，the pressure to build new water infrastructures has diminished over the past two decades． Although population，industrial output and economic productivity have continued to soar in developed nations，the rate at which people withdraw water from aquifers，rivers and lakes has slowed．And in a few parts of the world，demand has actually fallen．[573 words]
1．The author’s attitude toward the issue of dams is______．
A．optimistic
B．pessimistic
C．indifferent
D．worried
2．It is implied in the passage that______．
A．the author is proud of the huge number of dams built in the U．S．
B．the pressure to build new dams still exists especially in the developing world
C．a(chǎn)ll the environmentally harmful dams will be removed from rivers in the whole world
D．the ecosystems in the U．S．suffer most because of the numerous water infrastructures there
3．According to this passage，______．
A．big dams contribute little to the solution of water shortages
B．international financial organizations are mainly responsible for the environmental consequences of huge dams in the world
C．only a few species of animals suffer most from the consequences of water infrastructures
D．reducing the demand for water is much better than building more dams to solve water shortages
4．According to this passage，even______is／are faced with increasing opposition to building more big dams．
A．the World Bank
B．multilaterial aid agencies
C．many developing nations
D．many developed nations
5．The best title for this passage is______．
A．Damage from Dams
B．Environmental Awareness
C．The Future of Water Infrastructures
D．Water Shortages
In many nations，big dams and reservoirs were originally considered vital for national security， economic prosperity and agricultural survival．Until the late l970s and early l980s，few people took into account the environmental consequences of these massive projects．Today，however，the results are clear：dams have destroyed the ecosystems in and around countless rivers，lakes and streams．On the C01umbia and Snake rivers in the northwestern U．S．，95 percent of the juvenile salmon trying to reach the ocean do not survive passage through the numerous dams and reservoirs that block their way．More than 900 dams on New England and European rivers block Atlantic salmon from their spawning grounds， and their populations have falien to leSS than l percent of historical levels．
As environmental awareness has heightened globally，the desire to protect--and even restore--some of these natural resources has grown．The earliest environmental advocacy groups in the U．S．mobilized against dams proposed in places such as Yosemite National Park in California and the Grand Canyon in Arizona．In the l970s plans in the former Soviet Union to divert the flow of Siberian rivers away from the Arctic stimulated an unprecedented public outcry，helping to halt the projects．④In many developing countries，grassroots opposition to the environmental and social COSTS of big water projects is becoming more and more effective．Villagers and community activists in India have encouraged a public debate over major dams．
Until very recently．international financial organizations such as the World Bank，export-import banks and muhilateral aid agencies subsidized or paid in full for dams or other water-related civil engineering projects--which often have price tags in the tens of billions of dollars．These organizations are slowly beginning to reduce or eliminate such subsidies，putting more of the financial burden on already strained national economies．Having seen so much ineffective development in the past--and having borne the associated cOstS(both monetary and otherwise)of that development--many governments are unwilling to pay for new structures to solve water shortages and other problems．
A handful of countries are even taking steps to remove some of the most egregious and damaging dams．Altogether around 500 0ld，dangerous or environmentally harmful dams have been removed from U．S．rivers in the past few years．
Fortunately--and unexpectedly--the demand for water is not rising as rapidly as some predicted．As a result，the pressure to build new water infrastructures has diminished over the past two decades． Although population，industrial output and economic productivity have continued to soar in developed nations，the rate at which people withdraw water from aquifers，rivers and lakes has slowed．And in a few parts of the world，demand has actually fallen．[573 words]
1．The author’s attitude toward the issue of dams is______．
A．optimistic
B．pessimistic
C．indifferent
D．worried
2．It is implied in the passage that______．
A．the author is proud of the huge number of dams built in the U．S．
B．the pressure to build new dams still exists especially in the developing world
C．a(chǎn)ll the environmentally harmful dams will be removed from rivers in the whole world
D．the ecosystems in the U．S．suffer most because of the numerous water infrastructures there
3．According to this passage，______．
A．big dams contribute little to the solution of water shortages
B．international financial organizations are mainly responsible for the environmental consequences of huge dams in the world
C．only a few species of animals suffer most from the consequences of water infrastructures
D．reducing the demand for water is much better than building more dams to solve water shortages
4．According to this passage，even______is／are faced with increasing opposition to building more big dams．
A．the World Bank
B．multilaterial aid agencies
C．many developing nations
D．many developed nations
5．The best title for this passage is______．
A．Damage from Dams
B．Environmental Awareness
C．The Future of Water Infrastructures
D．Water Shortages