Paragraph 3
Within the ocean, the production of limestone, in the form of calcium carbonate skeletons or shells, also reduces atmospheric carbon dioxide. However, when deposits of limestone become exposed and weathered on land or are recycled in the sea, carbon dioxide is released back into the atmosphere. What is not well
understood is how much carbon dioxide resides in the sea and at what rate it is taken up and recycled. Relatively new research has also discovered beneath the sea a new and potentially significant threat to skyrocketing Earth temperature: gas hydrates. Gas hydrates are a solid, crystalline form of water, like ice, except that they contain additional gas, typically methane, and are often found stored in ocean sediments. Increased ocean temperatures could cause gas hydrates to dissociate, releasing massive amounts of methane gas into the atmosphere and cause undersea landslides in the process. Consequently, hydrates may, if released, significantly increase global warming as well as create a geologic hazard to offshore drilling operations.
7.According to paragraph 3, which of the following reduces atmospheric carbon dioxide?
A.The weathering of limestone B.The production of limestone C.The recycling of carbon dioxide
D.The presence of methane in gas hydrates
8.According to paragraph 3, why are gas hydrates a possible threat to the global climate?
A.If disturbed by offshore drilling, they can destroy limestone deposits.
B.They can replace regular ice at certain locations.
C.If melted, they may release a lot of carbon dioxide into the atmosphere.
D.They contain a lot of methane, which may be released as the ocean warms Paragraph 4
The ocean is also a great reservoir and transporter of heat. Heat from the ocean warms the atmosphere and fuels tropical storms. Heat is transported by currents from the equator to the poles. Ocean circulation is strongly controlled by wind and by the sea’s balance of salt and heat. Scientists think that climate warming may slow down circulation, while cooling may speed it up, but these responses are not well understood. Evaporation from the ocean also supplies the precipitation that creates fields of snow and ice at high latitudes. Snow and ice coverage change the reflectivity Earth’s surface and are an important influence on how much incoming radiation is either absorbed or reflected. Furthermore, clouds and water vapor in the atmosphere come mainly from the sea and strongly influence climate. Surprisingly, clouds are one of the least understood and most poorly modeled parts of the climate change equation. Most climate modeling grids fail to take into account common-sized cloud formations. Aerosols, tiny particles of soot, dust, and other materials, are thought to seed cloud formation scatter incoming radiation and promote cooling, but this effect, which would counteract warming, is also only superficially understood. Computer models of climate change must take into account all of the processes within the ocean, over land, and in the sky that potentially influence warming. No wonder there is such uncertainty.
9.The word “fuels” in the passage is closest in meaning to A.provides energy for B.determines the route of C.carries D.breaks up
10.Which of the following is NOT mentioned in paragraph 4 as a way in which the ocean affects the climate?
A.It stores heat
B.It moves heat from the equator toward the poles.
C.It speeds up wind circulation. D.It warms up the atmosphere.
11.Paragraph 4 suggests that a significant decrease in snow and ice fields at high latitudes would have what effect?
A.More clouds and water vapor would be produced in the atmosphere.
B.More of the Sun’s radiation would be absorbed by Earth. C.The oceans would cool more quickly.
D.More precipitation would occur at low latitudes.
12.Why does the author mention that “Most climate modeling grids fail to take into account common-sized cloud formations”?
A.To suggest why the influence of clouds on climate change is still undetermined
B.To explain why research on climate change does not focus on clouds
C.To help explain why it is unclear whether aerosols have the effect of counteracting warming
D.To explain in part why scientists are uncertain how much incoming radiation is absorbed or reflected
Paragraph 3
Within the ocean, the production of limestone, in the form of calcium carbonate skeletons or shells, also reduces atmospheric carbon dioxide. ■However, when deposits of limestone become exposed and weathered on land or are recycled in the sea, carbon dioxide is released back into the atmosphere. ■What is not well understood is how much carbon dioxide resides in the sea and at what rate it is taken up and recycled. ■Relatively new research has also discovered beneath the sea a new and potentially significant threat to skyrocketing Earth temperature: gas hydrates. ■Gas hydrates are a solid, crystalline form of water, like ice, except that they contain additional gas, typically methane, and are often found stored in ocean sediments. Increased ocean
temperatures could cause gas hydrates to dissociate, releasing massive amounts of methane gas into the atmosphere and cause undersea landslides in the process. Consequently, hydrates may, if released, significantly increase global warming as well as create a geologic hazard to offshore drilling operations.
13.Look at the four squares [■] that indicate where the following sentence could be added to the passage
Nor is carbon dioxide the only gaseous substance in the ocean that may affect climate.
Where would the sentence best fit?
14.Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selected 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.
The oceans affect the climate in numerous ways, some of which are poorly understood and therefore cannot be accurately modeled in computer climate programs.
Answer Choices
A.Estimates of future conditions are entered into supercomputers to calculate climate possibilities at various places on earth.
B.Oceans absorb a great deal of carbon dioxide from the air through limestone production and photosynthesis or phytoplankton.
C.Gases are stored in the sea in the form of shells and hydrates, but gases stored in these ways can be recycled to the atmosphere where they may cause warming.
D.The ocean's capacity to absorb carbon dioxide remains great despite recent reduction of marine plant nutrients such as iron.
E.Ocean circulation is strongly controlled by wind and by the sea s balance or salt and heat.
F.The ocean bolds and moves a great deal of heat, and as water
evaporates, it produces clouds, snow, and ice, which all affect global temperatures.
参考答案
1-5：DCACB 6-10：CBDAC 11-13：BAC 14：BCF
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