托福（阅读）历年真题试卷汇编7polkadot (题后含答案及解析)
题型有： 3. Reading Comprehension
out there>triplekill
metrology
Sections Three：Reading Comprehension
getwayRemoving DamsP1: In the last century, many of the dams in the United States were built for water diversion, agriculture, factory watermills, and other purpos that allowed farming on lands that would otherwi be too dry, with low-cost hydroelectric power generation being a very significant side benefit. Building the dams was rather labor-intensive, which created jobs for workers and stimulated regional economic development. But tho oppod to large dams can marshal a sobering array of criticisms bad on tho already built, which have provided some benefits but have without exception destroyed river environments and the human communities that depend on them.P2: Many, perhaps most, of the more than 90,000 dams in the country are now obsolete, expensive, and unsafe, and were built with no consideration of the environmental costs. As operating licens come up for renewal in 1
lfintroduction999, habitat restoration to original stream flows will be among the options considered. As the dams age and decay, they can also become public safety hazards, prenting a failure risk and a dangerous nuisance. Wor still, with the growth of the American population, more people are moving into risky areas. Dams that once could have failed without major repercussions are now upstream of cities and development. In 1998, the Army Corps announced that it would no longer be building large dams. In the few remaining sites where dams might be built, public opposition is so great that getting approval for projects is unlikely.P3: For many years, the United States Fish and Wildlife Service had advocated the removal of the Edwards Dam, which was built in 1837 on the Kennebec River in Augusta, Maine, to ea navigation and generate electricity. The Kennebec River was once home to all ten species of migratory fish native to Maine, along with veral thriving commercial fisheries. Damming the river not only transformed the natural landscape, but it also prevented migration of salmon, shad, sturgeon, and other fish species up the river.In 1999, the Federal Energy Regulatory Commission (FERC) refud the renewal of the dam licen due to excessive negative environmental impact,
and the dam was removed, freeing a 17-mile stretch of the Kennebec River that had been submerged for 162 years. P4: The cost of keeping outdated hydroelectric equipment running decades after it was installed or upgrading dam safety systems may not be worth it. This was proven true on the Elwha River in the Olympic National Park in Washington when an extraordinarily rich salmon habitat was being disrupted by an outdated hydroelectric plant. Before dams were built on the Elwha River, 400,000 salmon returned each year to spawn, but that number dropped to fewer than 3,000 after dams were put up. Once the hydroelectric power generating capacities of the dams had outlived their uful lives, the importance of this salmon habitat necessitated the removal of the dams on the Elwha River. Simply removing the dams will not restore the salmon, however. Where 50-kilogram king salmon once fought their way up waterfalls to lay their eggs in gravel beds, there are now only concrete walls holding back still water and deep beds of muddy deposits.P5: When the negative environmental effects outweigh the benefits, a dam may be considered for removal. The Hetch Hetchy Dam, who construction was one of the first major defeats of the nascent American environmental mthe fountainhead
正式英文>单挑英文ovement, was approved in 1913 to assist earthquake-ravaged San Francisco. Environmentalists and nature lovers, who said the valley’s beauty surpasd even Yomite Valleydrew’s, have constantly fought for its removal. They claim that restoring Hetch Hetchy Valley could reclaim an area that is half the size of Yomite Valley and nearly identical in terms of beauty. Revenue and incread local spending from tourism could offt some or all of the loss from removing the dam. This problem can be thought of as appraising the relative value of two scarce resources, water and space, in Yomite National Park.P6: How does one weigh the many different economic, cultural, and aesthetic considerations for removing or not removing the dams? Do certain interests, such as the rights of native people or the continued existence of native species of fish or wildlife, take precedence over economic factors, or should this be a utilitarian calculation of the greatest good for the greatest number? And does that number include only humans, or do other species count as well?P4: ■ The cost of keeping outdated hydroelectric equipment running decades after it was installed or upgrading dam safety systems may not be worth it. ■ This was proven true on the Elwha River in the Olympic N
ational Park in Washington when an extraordinarily rich salmon habitat was being disrupted by an outdated hydroelectric plant. ■ Before dams were built on the Elwha River, 400,000 salmon returned each year to spawn, but that number dropped to fewer than 3,000 after dams were put up. ■ Once the hydroelectric power generating capacities of the dams had outlived their uful lives, the importance of this salmon habitat necessitated the removal of the dams on the Elwha River. Simply removing the dams will not restore the salmon, however. Where 50-kilogram king salmon once fought their way up waterfalls to lay their eggs in gravel beds, there are now only concrete walls holding back still water and deep beds of muddy deposits.
