Many areas of theshallowsea bottom are covered with alushgrowth ofaquaticflowering plants adapted to live submerged in seawater. These plants arecollectivelycalled seagrasses. Seagrass beds are strongly influenced by severalphysicalfactors. The mostsignificantis water motion: currents and waves. Since seagrass systems exist in bothshelteredandrelativelyopen areas, they aresubjectto differing amounts of watermotion. For anygivenseagrass system, however, the watermotionisrelativelyconstant. Seagrass meadows inrelativelyturbulentwaterstendto form amosaicofindividualmounds, whereas meadows inrelativelycalmwaterstendto form flat,extensivecarpets. The seagrass beds, in turn, dampen waveaction, particularly if the bladesreachthe water surface. This damping effect can besignificantto the point where just one meter into a seagrass bed the wavemotioncan be reduced to zero. Currents are also slowed as they move into the bed.

The slowing of waveactionand currents means that seagrass bedstendtoaccumulatesediment. However, this is not universal and depends on the currents under which the bed exists. Seagrass beds under the influence of strong currentstendto have many of the lighter particles, including seagrassdebris, moved out, whereas beds in weakcurrentareasaccumulatelighter detritalmaterial. It is interesting thattemperateseagrass bedsaccumulatesediments from sources outside the beds, whereastropicalseagrass bedsderivemost of their sediments from within.

Since most seagrass systems are depositional environments, theyeventuallyaccumulateorganicmaterialthat leads to the creation offine-grainedsediments with a much higherorganiccontentthan that of the surrounding unvegetated areas. Thisaccumulation, in turn, reduces the water movement and theoxygensupply. The highrateofmetabolism(the processing of energy forsurvival) of the microorganisms in the sediments causes sediments to beanaerobic(withoutoxygen) below the first few millimeters. According to ecologist J. W. Kenworthy,anaerobicprocesses of the microorganisms in thesedimentare an importantmechanismfor regenerating and recycling nutrients andcarbon, ensuring the high rates ofproductivity—that is, theamountoforganicmaterialproduced-that are measured in those beds. Incontrastto otherproductivityin the ocean, which is confined to variousspeciesofalgaeandbacteriadependent onnutrientconcentrations in the watercolumn, seagrasses are rooted plants thatabsorbnutrients from thesedimentorsubstrate. They are,therefore,capableof recycling nutrients into theecosystemthat wouldotherwisebe trapped in the bottom and rendered unavailable.

Otherphysicalfactors that have an effect on seagrass beds include light,temperature, anddesiccation(drying out). For example, water depth and turbidity (densityof particles in the water) together or separately control theamountof lightavailableto the plants and the depth to which the seagrasses mayextend. Althoughmarinebotanist W. A. Setchell suggested early on thattemperaturewascriticalto the growth andreproductionof eelgrass, it has since been shown that this particularlywidespreadseagrass grows and reproduces at temperatures between 2 and 4 degrees Celsius in theArcticand at temperatures up to 28 degrees Celsius on the northeasterncoastof the United States. Still,extremetemperatures, incombinationwith other factors, may havedramaticdetrimentaleffects. For example, in areas of the cold North Atlantic, ice may form in winter. Researchers Robertson and Mann note that when the ice begins tobreakup, the wind and tides may move the ice around, scouring the bottom and uprooting the eelgrass. Incontrast, at the southern end of the eelgrass range, on the southeasterncoastof the United States, temperatures over 30 degrees Celsius in summer causeexcessivemortality. Seagrass beds alsodeclineif they are subjected to too muchexposureto the air. The effect ofdesiccationis often difficult toseparatefrom the effect oftemperature. Most seagrass beds seemtolerantofconsiderablechanges insalinity(salt levels) and can be found inbrackish(somewhatsalty) waters as well as in full- strength seawater.

Questions:
question_stem: According to paragraph 1, which of the following is true about seagrasses in calm ocean waters?
choices: tag: A
text: They will not survive for very long without the nutrients brought In by fast-moving waters.

tag: B
text: They tend to form beds covering large areas along the ocean floor.

tag: C
text: They usually are arranged in separate mounds.

tag: D
text: They grow more slowly than do seagrasses in fast-moving waters.
answer_key: B
explanation: 【题目翻译】根据第1段，关于平静海洋水域中的海草，以下哪项是正确的？
A：如果没有快速流动的水带来的营养，它们将无法存活很长时间。

B：它们倾向于在海底形成覆盖大面积的海床。

C：通常是分开的土堆。

D：它们比海草在快速流动的水中生长得慢。

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】：根据关键词“seagrasses”,定位到 Passage1，原句为“These plants are collectively called seagrasses. Seagrass beds are strongly influenced by several physical factors. The most significant is water motion: currents and waves. ”。意思是“这些植物统称为海草。海草床深受几个物理因素的影响。其中，最重要的因素是海水运动：海流和海浪。因为海草不仅生存在隐蔽的水域，也生存在相对开放的水域，因此海草需要去适应各种不同程度的水流运动。”。

【逻辑分析】：结合题目问法和出题句，进行逻辑分析。

【选项分析】
选项 A 没有快速流动的水流带来的营养，海草将不会存活很久。原文中并没有提及此信息；选项 B 它们会形成海草床覆盖海底的大部分区域，与原文信息一致；
选项 C 中的 separate mounds 只是原文的一个细节信息；
选项 D 中海草长得慢比起在流速快的水流中，原文并没有对此细节进行对比

question_stem: According to paragraph 1, which of the following is MOST likely to describe a bed in which seagrasses reach the surface of the water?
choices: tag: A
text: The water is almost completely still.

tag: B
text: The bed often has major damage from strong waves or currents.

tag: C
text: The bed is generally no more than one square meter in size.

tag: D
text: Grasses form a mosaic of individual mounds.
answer_key: A
explanation: 【题目翻译】根据第1段，以下哪项最可能描述海草到达水面的河床？
A：水几乎完全静止了。

B：河床经常受到巨浪或洋流的严重破坏。

C：床的尺寸一般不超过一平方米。

D：草形成一个由单个土堆组成的马赛克。

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】用 reach the surface of the water 定位到第一段倒数第三句，原句为“The seagrass beds, in turn, dampen wave action, particularly if the blades reach the water surface. ”，意思是：反过来，海草床也会减少波浪的作用，特别是当叶片长至水面以上时。

【逻辑分析】定位句强调了：当叶片到达水面的时候，水草会有抑制波浪的作用。

【选项分析】
A：如果有抑制作用发生，那么波涛就会变小甚至没有(下文也有相关描述)。A 为正确答案。
B：文章中未提及，故选项错误。
C：文章中未提及河床尺寸，故选项错误。
D：同样也未提及相关信息，故选项错误。

question_stem: Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
choices: tag: A
text: Light particles and debris collect in some seagrass beds, but are washed out of those affected by strong currents.

tag: B
text: Seagrass beds under the influence of strong currents tend to accumulate many of the lighter particles from other beds.

tag: C
text: The strength of the currents determines how quickly accumulated seagrass debris is moved out of the beds.

tag: D
text: Seagrass debris and other light particles are often moved from areas of strong currents to areas of weak currents.
answer_key: A
explanation: 【题目翻译】下面哪句话最能表达文章中突出显示的句子中的基本信息？错误的选择会以重要的方式改变意义，或者遗漏重要的信息。
A：轻颗粒和碎片在一些海草床上聚集，但被强洋流冲走。

B：在强洋流的影响下，海草床往往会从其他床层积聚许多较轻的颗粒。

C：洋流的强度决定了海草残骸从河床中移动的速度。

D：海草碎片和其他轻颗粒经常从强洋流区移到弱洋流区。

【判定题型】：根据题目问法，题目要求选择和高亮句意思逻辑都最为接近的句子，故判断本题为句子简化题。

【句子分析】这句话 whereas 前后之间构成转折关系。前半部分说的是，strong currents 况下,seagrass beds 会有很多较轻的 particles 移出，后半部分说的是，在 weak currents bed 会累积较轻的碎屑物质。

【选项分析】
A 表达了转折逻辑，以及与逻辑相关的意思。 正确
B 选项和原句说反。 错
C 选项 how quickly 在原句中并没有涉及到，错。 
D 选项中的 move out from…to 的这个逻辑将原句完全篡改，错。

question_stem: The word "derive" in the passage is closest in meaning to
choices: tag: A
text: maintain

tag: B
text: expel

tag: C
text: obtain

tag: D
text: enrich
answer_key: C
explanation: 【题目翻译】文章中的“派生”一词最接近于
A:保持
B:排除
C:拥有
D:丰富

【判定题型】：题目要求选出与高亮单词意思最接近的选项，故判断本题为词汇题。

【关键词定位】：根据关键词“derive”,定位到原句“It is interesting that temperate seagrass beds accumulate sediments from sources outside the beds, whereas tropical seagrass beds derive most of their sediments from within.”。

【词汇解析】：词汇“derive”的意思是“获得”,带入到原句中，原句的意思是“有趣的是，温带海草床通常会沉淀外来物，而热带海草床的沉积物通常来自海草床内部。”

【选项分析】
A:保持。不符，错误
B:排除。不符，错误
C:拥有。符合，正确
D:丰富。不符，错误

question_stem: According to paragraph 3, which of the following does NOT accurately describe the sediments that collect in seagrass beds?
choices: tag: A
text: Fine-grained

tag: B
text: Only a few millimeters deep

tag: C
text: Low in oxygen

tag: D
text: Rich in organic matter
answer_key: B
explanation: 【题目翻译】根据第3段，以下哪项不能准确描述海草床中收集的沉积物？
A：细粒

B：只有几毫米深

C：氧气不足

D：富含有机物

【判定题型】：根据题干中出现的大写“EXCEPT”/"NOT" 等其他明显表示否定的词，可以判定本题为否定事实信息题，需要找出与原文信息不符的那个答案。

【关键词定位】：根据题干关键词“sediments”,可以将出题范围锁定在 Passage 3 。

【选项分析】
选项 A 细粒的；正确
选项 B 仅有几毫米深与原文信息不符。错误
选项 C 低氧的；正确
选项 D 丰富的有机物，与原文的细节信息一致。正确

question_stem: The word "confined" in the passage is closest in meaning to
choices: tag: A
text: related

tag: B
text: limited

tag: C
text: relevant

tag: D
text: helpful
answer_key: B
explanation: 【题目翻译】文章中的“confined”一词最接近于
A:有关系的
B:受限制的
C:相关的
D:有用的

【判定题型】：题目要求选出与高亮单词意思最接近的选项，故判断本题为词汇题。

【关键词定位】：根据关键词“confined”,定位到原句“IIn contrast to other productivity in the ocean, which is confined to various species of algae and bacteria dependent on nutrient concentrations in the water column, seagrasses are rooted plants that absorb nutrients from the sediment or substrate. ”。

【词汇解析】：词汇“confined”的意思是“被限制的”,带入到原句中，原句的意思是“与海洋中其他生产力不同的是，海洋中的其他生产力仅限于依赖于水柱中营养物质浓度的各种藻类和细菌，海草是根植植物，从沉积物或基质中吸收营养物质。”

【选项分析】
A:有关系的。不符，错误
B:受限制的。同义替换，正确。
C:相关的。不符，错误
D:有用的。不符，错误

question_stem: According to paragraph 3, how do seagrasses affect the nutrient supply in the ecosystem?
choices: tag: A
text: Because of their high rate of metabolism, they consume a large percentage of the available nutrients.

tag: B
text: They attract various species of algae and bacteria that produce high nutrient concentrations in the water column.

tag: C
text: They take up carbon and other nutrients trapped on the sea bottom and bring them back into use.

tag: D
text: Through anaerobic processes at their roots, they produce a very nutrient-rich sediment.
answer_key: C
explanation: 【题目翻译】根据第3段，海草如何影响生态系统中的营养供应？
A：由于它们的高代谢率，它们消耗了大量可用营养素。

B：它们吸引各种藻类和细菌，这些藻类和细菌在水柱中产生高营养浓度。

C：它们吸收被困在海底的碳和其他营养物质，并重新投入使用。

D：通过它们根部的厌氧过程，它们产生了非常富营养的沉积物。

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】：根据关键词“xx”,定位到 Passage 3 第4句，原句为“According to ecologist J. W. Kenworthy, anaerobic processes of the microorganisms in the sediment are an important mechanism for regenerating and recycling nutrients and carbon, ensuring the high rates of productivity—that is, the amount of organic material produced-that are measured in those beds.”，意思是“根据生态学家 J•W•肯沃西所说，沉积物中微生物的无氧代谢是一项重要的使得营养物质和碳再生和循环的机制，保证了有机物的高产出率——即测量到的海草床中产生的有机物的量。”。

【逻辑分析】：结合题目问法和出题句，进行逻辑分析。

【选项分析】
A：不是海草床的高代谢率，而是微生物。故选项错误。
B：海草并不会吸引藻类和细菌。故选项错误。
C：选项中的 bring them back to use 与原文中的 regenerating and recycling 意思相符。正确。
D：海草不会产生沉积物。故选项错误。

question_stem: It can be inferred from paragraph 4 that the reason seagrasses do not grow in very deep water is that
choices: tag: A
text: they cannot handle intense water pressure

tag: B
text: deep water is too cold

tag: C
text: they would not get enough light

tag: D
text: deep water is too salty
answer_key: C
explanation: 【题目翻译】从第4段可以推断，海草不在很深的水中生长的原因是
A：它们不能承受巨大的水压。

B：深水太冷了

C：光不够亮

D：深水太咸了

【判定题型】：根据题干中出现的关键词“imply”/“infer”/“suggest”等其他表示推断的词，判定本题为推理题。

【关键词定位】：根据关键词“do not grow ”,定位到 Passage 4 第2句，原句为“For example, water depth and turbidity (density of particles in the water) together or separately control the amount of light available to the plants and the depth to which the seagrasses may extend.”。

【逻辑分析】水深和浊度一起或分别控制对植物可用的光的强度，并且这些海草的深度可能会延长。

【选项分析】
A：不符，错误
B：不符，错误
C：选项中海草将不会得到足够的光，与原文信息一致。正确。
D：不符，错误

question_stem: In paragraph 4, why does the author mention that eelgrass thrives in both the Arctic and in the northeastern United States?
choices: tag: A
text: To show that environments with extreme temperatures rarely have any effect on eelgrass

tag: B
text: To identify the northern and southern limits of the range where eelgrass is found

tag: C
text: To support the author's statement that eelgrass is a particularly widespread kind of seagrass

tag: D
text: To cite evidence tending to disprove one view about the importance of temperature to the growth of eelgrass
answer_key: D
explanation: 【题目翻译】在第4段中，作者为什么提到鳗鱼草在北极和美国东北部都很发达？
A：说明极端温度环境对鳗鱼草几乎没有任何影响。

B：确定发现鳗鱼草的地区的南北边界。

C：支持作者的说法，即鳗鱼草是一种特别广泛的海草。

D：引用一种倾向于反驳温度对鳗鱼草生长重要性的观点的证据。

【判定题型】：根据题干问法“why …… mention”，题目询问“xxxxxx”(文章引用内容)的修辞目的，可以判断本题为修辞目的题。

【关键词定位】：根据关键词“eelgrass.”,定位到 Passage 4 第6句，原句为“Researchers Robertson and Mann note that when the ice begins to break up, the wind and tides may move the ice around, scouring the bottom and uprooting the eelgrass. ”。

【引用内容分析】两个例子 Arctic 和 northeastern United States 的目的都是为了反驳观点：temperature was critical to the growth and reproduction of eelgrass。温度对鳗鱼的生长和繁殖至关重要。

【选项分析】
A 文章中说：夏季温度超过30摄氏度会造成大叶藻大量死亡。所以极端温度是有影响的。故选项错误。
B 段落主题不是确定鳗鱼草的地理位置。故选项错误。
C 文章是为了举例反驳温度对鳗鱼草生长重要性。错误
D 符合文意，正确。

question_stem: The word "detrimental" in the passage is closest in meaning to
choices: tag: A
text: harmful

tag: B
text: significant

tag: C
text: unexpected

tag: D
text: distinct
answer_key: A
explanation: 【题目翻译】文章中的“detrimenta”一词最接近于以下哪个选项？
A 有害的
B 重要的
C 意料之外的
D 明显的

【判定题型】：题目要求选出与高亮单词意思最接近的选项，故判断本题为词汇题。

【关键词定位】：根据关键词“detrimenta”,定位到原句“Still, extreme temperatures, in combination with other factors, may have dramatic detrimental effects. ”。

【词汇解析】：词汇“detrimenta”的意思是“不利的”,带入到原句中，原句的意思是“然而，极端温度与其他因素相结合，可能会产生巨大的不利影响。”。

【选项分析】
A 有害的。符合，正确
B 重要的。不符，错误
C 意料之外的。不符，错误
D 明显的。不符，错误

question_stem: Paragraph 4 suggests that which of the following would be the LEAST likely to cause major damage to eelgrass and other common seagrasses?
choices: tag: A
text: Factors related to extreme temperatures

tag: B
text: Exposure to air

tag: C
text: Major changes in salinity

tag: D
text: The movement of ice on the seafloor
answer_key: C
explanation: 【题目翻译】第4段提到，以下哪一项最不可能对鳗鱼草和其他常见海草造成重大损害？
A：与极端温度有关的因素

B：暴露在空气中

C：盐度的主要变化

D：海底冰的运动

【判定题型】：根据题干中出现的关键词“imply”/“infer”/“suggest”等其他表示推断的词，判定本题为推理题。

【关键词定位】：根据关键词“major damage”,定位到 Passage 4 ，原句为“Still, extreme temperatures, in combination with other factors, may have dramatic detrimental effects. ”。

【逻辑分析】极限温度结合其它的因素，会有显著的破坏作用。

【选项分析】
A：选项 A 不属于最少破坏的因素；
B：原文 Seagrass beds also decline if they are subjected to too much exposure to the air. 海草床也会减少如果它们太多的部分暴露在空气中，所以选项 B 也不属于最少的破坏因素；
C：原文 Most seagrass beds seem tolerant of considerable changes in salinity (salt levels) and can be found in brackish (somewhat salty) waters as well as in full- strength seawater. 大部分的海草似乎能承受相当大的盐分的变化，所以选项 C 中盐分的主要变化是最少的破坏因素。
D：选项 D 中海床上的冰的移动属于极限温度的一个表现，选项不属于最少的破坏影响。

question_stem: The phrase "tolerant of" in the passage is closest in meaning to
choices: tag: A
text: unused to

tag: B
text: strongly affected by

tag: C
text: protected from

tag: D
text: able to withstand
answer_key: D
explanation: 【题目翻译】文章中的“tolerant of”一词最接近于
A 不习惯于
B 强烈地受…影响
C 使免受
D 能够承受

【判定题型】：题目要求选出与高亮单词意思最接近的选项，故判断本题为词汇题。

【关键词定位】：根据关键词“tolerant of”,定位到原句“Most seagrass beds seem tolerant of considerable changes in salinity (salt levels) and can be found in brackish (somewhat salty) waters as well as in full- strength seawater. ”。

【词汇解析】：词汇“tolerant of”的意思是“容忍”,带入到原句中，原句的意思是“因为干化效应往往难以和高温效应分离开来。@@@@大多数的海草床都能适应各种盐度（盐含量）的变化，在半咸水（微咸）海域和纯咸水海域都能生存。”。

【选项分析】
A 不习惯于。不符，错误
B 强烈地受…影响。不符，错误
C 使免受。不符，错误
D 能够承受。符合，正确