1、大学英语四级改革适用（阅读）模拟试卷 217及答案与解析 Section B 0 Keep Our Seas Clean A) By the year 2050 it is estimated that the worlds population could have increased to around 12 billion. Of these, some 60 percent will live within 60 km of the sea. The agricultural and industrial activities required to support this popu
2、lation will increase the already significant pressures on fertile coastal areas. Death and disease caused by polluted coastal waters costs the global economy US $12.8 billion a year. Plastic waste kills up to 1 million sea birds, 100,000 sea mammals and countless fish each year. B) One significant i
3、mpact of human activity is marine pollution. The most visible and familiar is oil pollution caused by tanker accidents and tank washing at sea, and in addition to the gross visible short-term impacts, severe long-term problems can also result In the case of the Exxon Valdez which ran onto a shore in
4、 Alaska in 1989, biological impacts from the oil spill can still be identified 15 years after the event. The Prestige which sank off the Spanish coast late in 2002, resulted in huge economic losses as it polluted more than 100 beaches in France and Spain and effectively destroyed the local fishing i
5、ndustry. C) Despite the scale and visibility of such impacts, the total quantities of pollutants entering the sea from the long line of catastrophic oil spills appeared small compared with those of pollutants introduced directly and indirectly from other sources, including domestic sewage, industria
6、l discharges, leakages from waste tips, urban and industrial run-off, accidents, spillages, explosions, sea dumping operations, oil production, mining, agriculture nutrients and pesticides, waste heat sources, and radioactive discharges. Land based sources are estimated to account for around 44 perc
7、ent of the pollutants entering the sea and atmospheric inputs account for an estimated 33 percent. By contrast, transport on the sea accounts for 12 percent. D) The impacts of pollution vary. Nutrient pollution from sewage discharges and agriculture can result in unsightly and possibly dangerous “bl
8、ooms“ of algae (藻类 ) in coastal waters. As these blooms die and decay they use up the oxygen in the water. This has led, in some areas, to “creeping dead zones“ (CDZ), where oxygen dissolved in the water falls to levels unable to sustain marine life. Industrial pollution also contributes to these de
9、ad zones. E) Radioactive (放射性的 ) pollution has many causes, including the normal operation of nuclear power stations, but by far the single biggest sources of man-made radioactive elements in the sea are the nuclear fuel reprocessing plants at La Hague in France and at Sellafield in the UK Waste rel
10、eased from them has resulted in the widespread pollution of living marine resources over a wide area; radioactive elements traceable to reprocessing can be found in seaweeds as far away as the West Greenland Coast. F) Trace metal pollution from metal mining, production and processing industries can
11、damage the health of marine plants and animals and render some seafoods unfit for human consumption. The contribution of human activities can be very significant: the amount of mercury introduced to the environment by industrial activities is around four times the amount released through natural pro
12、cesses such as weathering and erosion (腐蚀 ). G) The input of man-made chemicals to the oceans potentially involves an overwhelming number of different substances. 63,000 different chemicals are thought to be in use worldwide with 3,000 accounting for 90 percent of the total production amount. Each y
13、ear, anywhere up to 1,000 new synthetic chemicals may be brought onto the market. Of all these chemicals some 4,500 fall into the most serious category. These are known as persistent organic pollutants (POPs). Theyre resistant to breakdown and have the potential to accumulate in the tissues of livin
14、g organisms (all marine life), causing hormone disruption which can, in turn, cause reproductive problems, induce cancer, suppress the immune system and interfere with normal mental development in children. H) POPs can also be transported long distances in the atmosphere and deposited in cold region
15、s. As a result, Inuit populations who live in the Arctic a long distance from the sources of these pollutants are among the most severely influenced people on the planet, since they rely on fat-rich marine food sources such as fish and seals. POPs are also thought to be responsible for some polar be
16、ar populations failing to reproduce normally. Scarily, seafoods consumed by people living in warm and mild regions are also affected by POPs. Oily fish tend to accumulate POPs in their bodies and these can be passed to human consumers. When oily fish are rendered down into fish meal and fish oils an
17、d subsequently used to feed other animals, then this too can act as a pathway to humans. Farmed fish and shellfish, dairy cattle, poultry and pigs are all fed fish meal in certain countries, and so meat and dairy products as well as farmed and wild fish can act as further sources of these chemicals
18、to humans. I) The North and Baltic Seas also contain some of the worlds busiest shipping lanes. 200,000 ships cross the North Sea every year. Many goods transported by ships are hazardous (half the goods carried at sea can be described as dangerous) and loss of dangerous cargoes can result in damage
19、 to the marine environment. Chemical tank washings, discharge of oily wastes and wash waters are all significant sources of marine pollution. J) In addition there is always the risk of a major oil spill, a risk made worse by the fact that some of the tankers that routinely travel through still have
20、only one body-frame or have other technical defects and crews who are poorly educated. In November 2002, the Prestige oil tanker went down off the coast of Spain with 70,000 tons of oil on board which polluted 2,890 km of coastline. A few days earlier it had been crossing the Baltic. K) Some sources
21、 of pollution have been brought under control by international legislation. Countries which signed the London Convention have agreed to stop the dumping of radioactive and industrial waste at sea. The OSPAR Convention regulates marine pollution in the North East Atlantic Region while countries which
22、 signed the Stockholm Convention have committed themselves to the phase out of a number of persistent organic pollutants. Within the European Community, the Water Framework Directive may be expected to bring further reductions in polluting inputs, although it will be over a very long time frame. The
23、 additional benefit of the new EU REACH (Registration Evaluation and Authorisation of Chemicals) initiative, which aims to regulate the production and use of dangerous chemicals at source, remains to be seen. 1 The regulation of marine pollution in the North East Atlantic Region is based on the OSPA
24、R Convention. 2 The fact that some tankers still have only one body-frame or have other technical defects making bigger possibility of oil spill. 3 About one-third of the pollutants entering the sea come from atmospheric inputs. 4 The overgrow of algae will result in oxygen shortage in the water, wh
25、ich led to “creeping dead zones“. 5 In warm and mild regions, farmed fish and shellfish are also affected by POPs because they are fed fish meal. 6 As long as 2,890 km of coastline had been polluted by the oil spill of the Prestige oil tanker. 7 Oil pollution caused by tanker accidents and tank wash
26、ing at sea is considered as the most visible and familiar marine pollution. 8 Half of the goods transported by ships can be classified as dangerous cargoes. 9 The West Greenland Coast has been polluted by radioactive elements. 10 Hormone disruption in marine life is the result of accumulation of POP
27、s. 10 Working to Improve the Conditions of Everglades National Park A) When many people think of Florida, images of sandy coastlines or theme park rides come to mind. But about an hour south of Miami lies a natural wilderness different from anywhere else in the United States. Everglades National Par
28、k is the largest subtropical wilderness in the country. The park is home to several rare and endangered species. It is also the third largest national park in the lower forty-eight states, after Death Valley and Yellowstone. More than one million people visit the Everglades each year. B) The Evergla
29、des is considered one of the great biological wonders of the world. The expansive wetlands stretch across more than six hundred thousand hectares (公顷 ). It is a place where plants and animals from the Caribbean Sea share an ecosystem with native North American species. Unlike most other national par
30、ks, Everglades National Park was created to protect an ecosystem from damage. The Everglades is home to thirty-six species that are considered threatened or protected. They include the Florida panther, the American crocodile and the West Indian manatee. In addition, more than three hundred fifty bir
31、d species and three hundred species of fresh and saltwater fish live within the park. The Everglades is also home to forty species of mammals (哺乳动物 ) and fifty reptile (爬行动物 ) species. C) Exotic plants can also be found in the Everglades. They include what is said to be the largest growth of mangrov
32、e trees in the western half of the world. Gumbo-limbo trees, known for their peeling red skin, strangler figs and royal palms are also among the areas plant life. The Everglades is also home to the countrys largest living mahogany tree. Sawgrass grows in some areas of the park. Be careful it is very
33、 sharp, with teeth just like a saw. It can grow up to four meters tall. With about one and one-half meters of rainfall each year, plants and trees never stop growing in the Everglades. D) The dry, winter season is the favorite of most visitors, when insects like mosquitoes are less of a problem. The
34、 rainy season lasts from June to November. There are many ways to explore the Everglades. Visitors could see American crocodiles while hiking the Anhinga Trail. The Everglades is the only place on Earth where fresh water crocodiles and saltwater crocodiles live in the same area. Visitors using canoe
35、s or airboats are likely to see large groups of wading birds like the wood stork or great blue heron. It is even possible to see flamingos in the Everglades. This spring, Everglades National Park launched a visitation program to what was once a highly restricted military base. Park officials are wor
36、king to recover a missile base used in the 1960s. The base played a Part In the nuclear tensions between the United States and the Soviet Union. E) The government built the Florida base shortly after the discovery of Soviet missiles about three hundred kilometers away, on the island of Cuba. Tension
37、s were high during the Cuban missile crisis. But missiles stored at the American base were never fired. The base was closed and all missile equipment was removed in the 1970s. Today only the buildings remain. This year, the historic area had many visitors, including former American service members w
38、ho remember the missile crisis. The park hopes to offer more trips next spring, to help support the history for those who lived through it and for future generations. F) Experts say changes to the Everglades are threatening several different kinds of wildlife. They say the threats are a result of ac
39、tions the United States government began more than fifty years ago, and settlers began even earlier. The National Park Service says early colonial settlers and land developers thought the Everglades had little value. The settlers had plans to remove water from the area and in the 1880s developers be
40、gan digging drain canals. At the time, they did not understand the complexity of the Everglades ecosystem. As a result, they were not prepared for all the work and caused environmental problems. The ecosystem, however, was able to survive. G) Even larger efforts to drain the wetlands continued betwe
41、en 1905 and 1910. Large areas were changed to farmland. This led to increased development, with more people moving to the Everglades and also more visitors. More changes came in 1948, when Congress approved the Central and South Florida Project. As part of the plan, the Army Corps of Engineers built
42、 roads, canals and water-control systems throughout South Florida The aim of the project was to provide water and flood protection for developed areas and agriculture. Workers built a huge system of waterways and pumping stations to control the overflow of Lake Okeechobee, north of the Everglades. T
43、oday, fifty percent of south Floridas early wetland areas no longer exist. Populations of wading birds have been reduced by ninety percent. Whole populations of animals are in danger of disappearing. The endangered creatures include the manatee, the Miami blackhead snake, the wood stork and the Flor
44、ida panther. H) In recent years, environmental experts have learned about the damage to the Everglades. They say the natural balance of plants and animals has been destroyed. Recently, the Obama administration promised three hundred sixty million dollars to pay for Everglades restoration this year.
45、The administration is also asking that Congress approve an additional two hundred seventy-eight million dollars for next year. The money will help to support projects approved by the government nine years ago. The projects include improving wetlands in the Picayune Strand in Southwest Florida and re
46、pairs to Lake Okeechobees dam. Until now, the state of Florida has spent the most money on the project. I) Another threat biologists have been battling for years in the Everglades is the areas population of Burmese pythons (large snakes). Officials believe there are as many as one hundred fifty thou
47、sand of these large snakes in the Everglades. But the snakes are a foreign species, native to Southeast Asia Owners of pythons left their unwanted snakes in the Everglades years ago. Biologists say adult pythons are able to eat small deer and bobcats. When pythons are found in the Everglades, they a
48、re often killed. Scientists are now experimenting with other ways to remove the snakes, including trapping methods and offering payments to hunters. The future of the Everglades is not clear. However, efforts to protect the area are continuing so that people from all over the world may continue visi
49、ting this biological treasure. 11 Efforts to protect the area would be continued though the future of Everglades is still unknown. 12 In order to provide water and flood protection for developed areas and agriculture, the Congress approved the Central and South Florida Project. 13 The Soviet Union placed missiles on the island of Cuba during the Cuban missile crisis. 14 With an ecosystem of plants and animals both from Caribbean Sea and North American, Everglades National Park aims at protecting an ecosystem from damage. 15 There are only ten percent of wading birds still existin
