5. The word "exceedingly" in the passage is closest in meaning to
O unusually
O dangerously
O surprisingly
O highly
词汇题
解析：Spartina is an exceedingly competitive plant.用来修饰“有竞争力的”，根据文章可知是“十分”有竞争力的，起到强调作用，选4
6. According to paragraph 3, one reason that Spanina is able to compete in marsh environments so successfully is its ability to
O alter the substrate in which it grows
O convert sulfides into a usable form of sulfur
O grow and produce seeds while floating on the surface of the water
O produce carbon dioxide with great efficiency
细节题
定位词：marsh environments，its ability
解 析：Spartina has the ability to take up sulfides and convert them to sulfate, a form of sulfur that the plant can use; this ability makes it easier for the grass to colonize marsh environments.因为它可以将吸收硫化物，并转换成为硫酸盐。选2
Paragraph 4: These characteristics make Spartina a valuable component of the estuaries where it occurs naturally. The plant functions as a stabilizer and a sediment trap and as a nursery area for estuarine fish and shellfish. Once established, a stand of Spartina begins to trap sediment, 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 increases, 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 used for coastal restoration projects and the creation of new wetland sites.
7. Paragraph 4 suggests that where Spanina occurs naturally, an established stand of it will eventually
O create conditions in which it can no longer survive
O get washed away by water flowing through the deep channels that form around it
O become adapted to brackish water
O take over other grass species growing in the area
推断题
定位词：an established stand
解 析：Once established, a stand ofSpartina begins to trap sediment, 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.一旦米草植物定下来，就开始吸收沉淀物，改变基质的海拔高度，最终这地方会更高海拔的微咸淡水植物取代，发展成一个高海拔沼泽地。选1， 创造是自己不能存活的条件
8. According to paragraph 4, in its natural habitats, Spanina helps estuaries by
O controlling marshland decline
O decreasing the substrate elevation
O reducing the brackishness of the water
O increasing the flow of water into the estuary
细节题
定位词：Spanina helps estuaries
解 析：Along the east coast Spartina is considered valuable for its ability to prevent erosion and marshland deterioration;帮助阻止沼泽地的退化，选1
Paragraph 5: Spartina was transported to Washington State in packing materials for oysters transplanted from the east coast in 1894. Leaving its insect 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 sediment. Spartina modifies tidal mudflats, turning them into high marshes inhospitable to the many fish and waterfowl that depend on the mudflats. It is already hampering the oyster harvest and the Dungeness crab fishery, and it interferes with the recreational use 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 use the marsh.
9. The word "modifies" in the passage is closest in meaning to
O creates
O changes
O grows on
O breaks down
词汇题
解 析：Spartina modifies tidal mudflats, turning them into high marshes inhospitable to the many fish and waterfowl that depend on the mudflats.上下文关系，米草植物___沿海滩涂，将他们转变成不适合很多一拉滩涂的鱼类和水禽的沼泽地，填入“改变”，选2
Paragraph 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 these methods and is presently using the herbicide glyphosphate to control its spread. Work has begun to determine the feasibility of using insects as biological controls, but effective biological controls are considered years away. Even with a massive effort, it is doubtful that complete eradication of Spartina from nonnative habitats is possible, for it has become an integral part of these shorelines and estuaries during the last 100 to 200 years.
10. The word "Efforts" in the passage is closest in meaning to
O Laws
O Suggestions
O Attempts
O Failures
词汇题：
解 析：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.之后都是控制米草植物的方法，所以选择3
11. According to paragraph 5, Spanina negatively affects wildlife in estuaries by
O trapping fish and waterfowl in sediment
O preventing oysters from transplanting successfully
O turning mudflats into high marshes and salt meadows
O expanding the marshy fringes of salt meadows
细节题
定位词：negatively affects wildlife in estuaries
解 析：Spartina modifies tidal mudflats, turning them into high marshes inhospitable to the many fish and waterfowl that depend on the mudflats. It is already hampering the oyster harvest and the Dungeness crab fishery, and it interferes with the recreational use of beaches and waterfronts.
“hamper”“interfere”强调spartina改变沿海滩涂的副作用，选3
12. According to paragraph 6, each of the following methods has been used in attempts to control Spanina EXCEPT
O flooding plants
O cutting plants down repeatedly
O applying herbicides
O introducing predatory insects
排除题
定位词：methods has been used in attempts to control Spanina
解 析：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.
1,2,3都提到，选择4
13. Look at the four squares [Ⓐ] [Ⓑ] [Ⓒ] and [Ⓓ] that indicate where the following sentence could be added to the passage.
Spartina is particularly able to tolerate high salinities because salt glands on the surface of the leaves remove the salt from the plant sap.
Where would the sentence best fit?
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 seeds float into a suitable area and germinate. Ⓑ Spartina establishes itself 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). Ⓒ Because they lack oxygen, marsh sediments 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 use; this ability makes it easier for the grass to colonize marsh environments. Another adaptive advantage is Spartina’s ability to use carbon dioxide more efficiently than most other plants.
14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.
Spanina alrerniflora, or cordgrass, is the dominant native species in salt marshes along the Atlantic coast and the Gulf Coast of the United States.
Click on 3 answers.
O Spartina is very well adapted to conditions in salt marshes, where it plays a valuable role in stabilizing them and making them highly productive marine habitats.
O Spartina expands by growing root systems that float on the water’s surface and descend underground, where it finds the nutrients that it needs to germinate.
O As a result of its spread in Washington State over the past hundred years. Spartina has now become a threat to native oysters by releasing sediments that contain sulfides into the waters.
O The dead leaves of Spartina become food for a wide variety of marine organisms.
O Outside its native regions, Spartina can pose serious problems by turning mudflats into high marshes that are inhospitable to many native fish and birds.
O Spartina has physiological adaptations that allow it to grow in environments where other plants cannot, making it a very strong competitor that is difficult to control once it is established.
总结题
解析：分析黑体字：Spanina alrerniflora, or cordgrass, is the dominant native species in salt marshes along the Atlantic coast and the Gulf Coast of the United States.
O Spartina is very well adapted to conditions in salt marshes, where it plays a valuable role in stabilizing them and making them highly productive marine habitats.第二段观点，米草植物适合在盐碱沼泽地生存
O Spartina expands by growing root systems that float on the water’s surface and descend underground, where it finds the nutrients that it needs to germinate.原文没有提到该信息
O As a result of its spread in Washington State over the past hundred years.Spartina has now become a threat to native oysters by releasing sediments that contain sulfides into the waters.细节排除
O Thedead leaves of Spartina become food for a wide variety of marine organisms.细节排除
O Outside its native regions, Spartina can pose serious problems by turning mudflats into high marshes that are inhospitable to many native fish and birds.第五段观点，米草植物改变滩涂使得鱼类等不能生存
O Spartina has physiological adaptations that allow it to grow in environments where other plants cannot, making it a very strong competitor that is difficult to control once it is established.第三段观点，米草植物的优势
参考答案：
1. A
2. C
3. D
4. B
5. D
6. B
7. A
8. A
9. B
10. C
11. C
12. D
13. C
14. Spartina is very well ...
Outside its native regions ...
Spartina has physiological ...
