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托福阅读TPO22(试题+答案+译文)第1篇:Spartina
放的反义词托福阅读原文
【1】Spartina alterniflora, known as cordgrass, is a deciduous, perennial flowering plant native to the Atlantic coast and the Gulf Coast of the United States. It is the dominant native species of the lower salt marshes along the coasts, where it grows in the intertidal zone (the area covered by water some parts of the day and expod others).
大灰狼的叫声【2】The natural salt marshes are among the most productive habitats in the marine environment. Nutrient-rich water is brought to the wetlands during each high tide, making a high rate of food production possible. As the aweed and marsh grass leaves die, bacteria break down the plant material, and incts, small shrimplike organisms, fiddler crabs, and marsh snails eat the decaying plant tissue, digest it, and excrete wastes high in nutrients. Numerous incts occupy the marsh, feeding on living or dead cordgrass tissue, and redwing blackbirds, sparrows, rodents, rabbits, and deer feed directly on the cordgrass. Each tidal cycle carries plant material into the offshore water to be ud by the subtidal organisms.
【3】Spartina is an exceedingly competitive plant. It spreads primarily by underground stems; colonies form when pieces of the root system or
whole plants float into an area and take root or when eds float into a suitable area and germinate. Spartina establishes itlf on substrates ranging from sand and silt to gravel and cobble and is tolerant of salinities ranging from that of near freshwater (0.05 percent) to that of salt water (3.5 percent). Becau they lack oxygen, marsh diments are high in sulfides that are toxic to most plants. Spartina has the ability to take up sulfides and convert them to sulfate, a form of sulfur that the plant can u; this ability makes it easier for the grass to colonize marsh environments. Another
adaptive advantage is Sparti na’s ability to u carbon dioxide more efficiently than most other plants.乌龟种类鉴别图片
【4】The characteristics make Spartina a valuable component of the estuaries where it occurs naturally. The plant functions as a stabilizer and a diment trap and as a nurry area for estuarine fish and shellfish. Once established, a stand of Spartina begins to trap diment, changing the substrate elevation, and eventually the stand evolves into a high marsh system where Spartina is gradually displaced by higher-elevation, brackish-water species. As elevation increas, narrow, deep channels of water form throughout the marsh. Along the east coast Spartina is considered valuable for its ability to prevent erosion and marshland deterioration; it is also ud for coastal restoration projects and the creation of new wetland sites.
【5】Spartina was transported to Washington State in packing materials
for oysters transplanted from the east coast in 1894. Leaving its inct predators behind, the cordgrass has been spreading slowly and steadily along Washington’s tidal estuaries on the west coast, crowding out the native plants and drastically altering the landscape by trapping diment. Spartina modifies tidal mudflats, turning them into high marshes inhospitable to the many fish and w
aterfowl that depend on the mudflats. It is already hampering the oyster harvest and the Dungeness crab fishery, and it interferes with the recreational u of beaches and waterfronts. Spartina has been transplanted to England and to New Zealand for land reclamation and shoreline stabilization. In New Zealand the plant has spread rapidly, changing mudflats with marshy fringes to extensive salt meadows and reducing the number and kinds of birds and animals that u the marsh.
【6】Efforts to control Spartina outside its natural environment have included burning, flooding, shading plants with black canvas or plastic, smothering the plants with dredged materials or clay, applying herbicide, and mowing repeatedly. Little success has been reported in New Zealand and England; Washington State’s management program has tried many of the methods and is prently using the herbicide glyphosphate to control its spread. Work has begun to determine the feasibility of using incts as biological controls, but effective biological controls are considered years away. Even with a massive effort, it is doubtful that
女人带貔貅的正确方法complete eradication of Spartina from nonnative habitats is possible, for it has become an integral part of the shorelines and estuaries during the last 100 to 200 years.
托福阅读试题
女人吃葛根粉有什么好处
1.According to paragraph 1, each of the following is true of Spartina alrerniflora EXCEPT:
A.It rarely flowers in salt marshes.
B.It grows well in intertidal zones.
单翅天使C.It is commonly referred to as cordgrass.
D.It occurs naturally along the Gulf Coast and the Atlantic coast of the United States.
2.According to paragraph 2, a major reason why natural salt marshes are so productive is that they are
A.inhabited by long-lived aweed and marsh grass that reproduce gradually.
B.kept clear of excess plant material by the tides.
D.home to a wide variety of different species of grass.
3.Which of the ntences below best express the esntial information in the highlighted ntence in the passage? Incorrect choices change the
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