Many plants – one or morespeciesof atleast68 different families – cansecretenectarevenwhen they have no blossoms, because theybearextrafloral nectaries (structures that producenectar) on stems, leaves, leaf stems, or other structures. These plants usuallyoccurwhere ants areabundant, most in the tropics but some intemperateareas. Among those of northeastern North America are various plums, cherries, roses, hawthorns, poplars, and oaks. Likefloralnectar, extrafloralnectarconsists mainly of water with a highcontentof dissolved sugars and, in some plants, small amounts ofaminoacids. The extrafloral nectaries of some plants are known toattractants and other insects, but theevolutionaryhistoryof most plants with these nectaries is unknown. Nevertheless, most ecologists believe that all extrafloral nectariesattractinsects that willdefendthe plant.

Ants are probably the most frequent and certainly the mostpersistentdefenders of plants. Since the highly active worker antsrequirea greatdealof energy, plantsexploitthis need by providing extrafloralnectarthat supplies ants withabundantenergy. To return thisfavor, ants guard the nectaries, driving away or killing intruding insects that mightcompetewith ants fornectar. Many of these intruders areherbivorousand would eat the leaves of the plants.

Biologists once thought thatsecretionof extrafloralnectarhas some purelyinternalphysiologicalfunction, and that ants provide nobenefitwhatsoever to the plants thatsecreteit. This view and the opposing “protectionist”hypothesisthat antsdefendplants had been disputed for over a hundred years when, in 1910, askepticalWilliam Morton Wheeler commented on thecontroversy. He called forproofof the protectionist view: that visitations of the antsconferprotection on the plants and that in theabsenceof the insects a much greater number wouldperishor fail to produce flowers or seeds than when the insects are present. That we now have anabundanceof theproofthat was called for was established when Barbara Bentley reviewed therelevantevidencein 1977, and since then many more observations and experiments have provided still furtherproofthat antsbenefitplants.

One example shows how ants attracted to extrafloral nectaries protect morning glories against attacking insects. Theprincipalinsectenemies of the North American morning glory feed mainly on its flowers or fruits rather than its leaves. Grasshoppers feeding on flowers indirectlyblockpollinationand the production of seeds by destroying the corolla or thestigma, which receives thepollengrains and on which thepollengerminates. Without their colorful corolla, flowers do notattractpollinators and are notfertilized. An adultgrasshoppercanconsumea large corolla, about 2.5 inches long, in an hour. Caterpillars and seed beetlesaffectseed production directly. Caterpillarsdevourthe ovaries, where the seeds are produced, and seed beetlelarvaeeat seeds as theyburrowin developing fruits.

Extrafloral nectaries at the base of each sepalattractseveral kinds of insects, but 96 percent of them are ants, several differentspeciesof them. When buds are still small, less than a quarter of an inch long, the sepal nectaries are already present and producingnectar. They continue to do so as the flower develops and while the fruit matures. Observations leave littledoubtthat ants protect morning glory flowers and fruits from the combined enemy force of grasshoppers, caterpillars, and seed beetles. Bentley compares the seed production of six plants that grew where there were no ants with that of seventeen plants that were occupied by ants. Unprotected plants bore only 45 seeds per plant, but plants occupied by ants bore 211 seeds per plant. Although ants are not big enough to kill or seriously injure grasshoppers, theydrivethem away by nipping at their feet. Seed beetles are morevulnerablebecause they are much smaller than grasshoppers. The antspreyon the adult beetles,disturbfemales as theylaytheir eggs on developing fruits, and eat many of the eggs they domanagetolay.

Questions:
question_stem: According to paragraph 1, floral nectar and extrafloral nectar are alike in that
choices: tag: A
text: they are likely to be produced by the same plants

tag: B
text: they basically consist of the same chemical components

tag: C
text: they attract only insects that will defend the plant

tag: D
text: they are produced by the same parts of the plant
answer_key: B
explanation: 【题目翻译】根据第1段，花蜜和花外花蜜在这哪方面是相似的？
A：可能是同一种植物生产的

B：它们基本上由相同的化学成分组成

C：它们只吸引能保护植物的昆虫

D：它们是由植物的同一部分生产的

【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“alike”,定位到 Passage 1 第4句，原句为“Like floral nectar, extrafloral nectar consists mainly of water with a high content of dissolved sugars and, in some plants, small amounts of amino acids.”，意思是“花蜜一样，花外花蜜主要包括水，高浓度的溶解糖，在某些植物里，还有少量的氨基酸。”

【逻辑分析】从定位句就可以看出 floral nectar 和 extrafloral nectar 有相似的成分。

【选项分析】
A.未提及是否是由同一种植物产生的，故错误。
B.符合文意，故正确。
C.还有可能吸引对植物有害的昆虫，故错误。
D.所处地方不一样，在茎，叶子，叶茎或其他结构上有花外蜜腺。故错误。

question_stem: To say that ants are “persistent” defenders of plants means that
choices: tag: A
text: they defend plants against a wide variety of threats

tag: B
text: they continue to defend plants for as long as the plants are threatened

tag: C
text: they are successful defenders of plants

tag: D
text: they are easily observable defenders of plants
answer_key: B
explanation: 【题目翻译】如果说蚂蚁是植物的“坚持不懈的”捍卫者，那就意味着
A：他们保护植物免受各种各样的威胁

B：只要植物受到威胁，他们就继续保护植物

C：他们是植物的成功卫士

D：它们很容易观察到植物的防御者。

【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“persistent”,定位到 Passage 2第1句，原句为“Ants are portably the most frequent and certainly the most persistent defenders of plants.”，意思是“蚂蚁或许是植物的最常见也无疑是最执著的保护者了。”

【逻辑分析】此题等于就是在考查学生对于 persistent 词义的理解。persistent，坚持的/固执的。

【选项分析】
A.提到了保护，但是没有提到“坚持”保护，故错误。
B.其对应 B 选项的 continue to defend plants，给予植物持久的保护。
C.没有提到“坚持”保护，故错误。
D.没有提到“坚持”保护，故错误。

question_stem: What can be inferred from paragraph 2 about the ants that are attracted to the extrafloral nectaries?
choices: tag: A
text: They do not eat the leaves of the plants that produce extrafloral nectar.

tag: B
text: They live almost entirely on extrafloral nectar.

tag: C
text: They spend most of their energy guarding extrafloral nectaries.

tag: D
text: They frequently fight among themselves over extrafloral nectar.
answer_key: A
explanation: 【题目翻译】以下哪一个可以从第2段可以推断出蚂蚁被花外蜜腺所吸引？
A：它们不吃那些产生花外花蜜的植物的叶子。

B：它们几乎完全靠花外花蜜生活。

C：它们把大部分精力花在保护花外花蜜上。

D：它们经常为花外花蜜而争吵。

【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“the extrafloral nectaries”,定位到 Passage 2，原句为“Ants are portably the most frequent and certainly the most persistent defenders of plants. Since the highly active worker ants require a great deal of energy, plants exploit this need by providing extrafloral nectar that supplies ants with abundant energy. To return this favor, ants guard the nectaries, driving away or killing intruding insects that might compete with ants for nectar.”。

【逻辑分析】本段解释了为什么蚂蚁或许是植物的最常见也无疑是最执著的保护者。

【选项分析】
A.符合文意，故正确。
B.“几乎”和“完全”一次用得过于绝对，且文章也未提及，故错误。
C.文章未说蚂蚁把大部分精力放在那里，故错误，只提到了为了回报植物，蚂蚁会保卫蜜腺。
D.文章未提及，故错误。

question_stem: According to paragraph 3, what was the position of the opponents of the “protectionist” hypothesis?
choices: tag: A
text: Extrafloral nectar provides plants with a direct defense against attack by insects.

tag: B
text: Ants substantially benefit plants that secrete extrafloral nectar.

tag: C
text: The secretion of extrafloral nectar plays a role in the plant’s internal functioning.

tag: D
text: Ants visit plants that secrete extrafloral nectar as often as they visit plants that do not.
answer_key: C
explanation: 【题目翻译】根据第3段，反对“保护主义”假设的人的立场是什么？
A：花外花蜜为植物提供了直接防御昆虫攻击的能力。

B：蚂蚁对分泌花外花蜜的植物大有好处。

C：花外花蜜的分泌对植物的内部功能起着一定的作用。

D：蚂蚁访问分泌花外花蜜的植物和访问不分泌花外花蜜的植物一样频繁。

【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“the opponents of the “protectionist” hypothesis”,定位到 Passage3第2句，原句为“This view and the opposing “protectionist” hypothesis that ants defend plants had been disputed for over a hundred years when, in 1910, a skeptical William Morton Wheeler commented on the controversy. ”，意思是“人们就该观点及其反方观点争执了很多年。反方观点坚持“保护主义者”假说，认为蚂蚁能够保护植物。1910年，怀疑论者威廉莫尔顿惠勒对这一争议做出了评论。”

【逻辑分析】但是定位句这句话只说了这个观点和保护主义假说的反对意见受到争议，所以他们具体的立场应该看首句 Biologists once thought that secretion of extrafloral nectar has some purely internal physiological function, and that ants provide no benefit whatsoever to the plants that secrete it.

【选项分析】
A.是内部功能不是外部防御昆虫，故错误。
B.不是花外，是花的内部功能，故错误。
C.文章说：外部花蜜的分泌物只是对植物有内部生理作用，蚂蚁没有作用，对应 C 选项。
D.文章未提及两者的频率，也未比较，故错误。

question_stem: The word “skeptical” in the passage is closest in meaning to
choices: tag: A
text: curious

tag: B
text: doubtful

tag: C
text: open-minded

tag: D
text: practical
answer_key: B
explanation: 【题目翻译】文章“skeptical”与下列哪一个意思最相近？
A：curious，好奇的
B：doubtful，怀疑的
C：open-minded，思路活跃的
D：practical，实际的

【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“skeptical”,定位到原句“This view and the opposing “protectionist” hypothesis that ants defend plants had been disputed for over a hundred years when, in 1910, a skeptical William Morton Wheeler commented on the controversy. ”。

【词汇解析】：词汇“skeptical”的意思是“怀疑的”,带入到原句中，原句的意思是“人们就该观点及其反方观点争执了很多年。反方观点坚持“保护主义者”假说，认为蚂蚁能够保护植物。1910年，怀疑论者威廉莫尔顿惠勒对这一争议做出了评论。”

【选项分析】
A：curious，好奇的，不符，错误
B：doubtful，怀疑的，同义替换，正确
C：open-minded，思路活跃的，不符，错误
D：practical，实际的，不符，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: We now have ample proof that ants benefit plants.

tag: B
text: Barbara Bentley has called for additional proof that ants benefit plants.

tag: C
text: In 1977 Barbara Bentley conducted research that proved that all prior studies were wrong.

tag: D
text: Proof that ants benefit plants will require many more observations and experiments.
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：我们现在有充分的证据证明蚂蚁有益于植物。

B：芭芭拉·本特利要求提供更多证据证明蚂蚁有益于植物。

C：1977年，芭芭拉·本特利进行了一项研究，证明所有先前的研究都是错误的。

D：证明蚂蚁有益于植物需要更多的观察和实验。

【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】这句话看似很长，实际重点内容就是 We now have an abundance of the proof and since then many more observations and experiments have provided still further proof that ants benefit plants.我们现在有很多之前的证据和在1977年以后做的各种观察和实验来证明蚂蚁对植物有好处。

【选项分析】
A.与文章相符，故正确。
B.现在已经有了充足的证据了，故选项错误。
C.未说以前的研究都是错的，故选项错误。
D.现在已经有充分的证据证明蚂蚁有益于植物了，故选项错误。

question_stem: According to paragraph 4, what effect does the destruction of the corolla have on plants?
choices: tag: A
text: It leaves the seeds exposed and unprotected.

tag: B
text: It prevents the stigma from developing.

tag: C
text: It keeps pollen grains from attaching properly.

tag: D
text: It prevents the flower from attracting pollinators.
answer_key: D
explanation: 【题目翻译】根据第4段，花冠的破坏对植物有什么影响？
A：它会让种子暴露在外，不受保护。

B：它可以防止柱头的形成。

C：它能防止花粉粒正确附着。

D：它能防止花吸引授粉者。

【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】
通过 the destruction of the corolla 定位至 Without their colorful corolla, flowers do not attract pollinators and are not fertilized.意思是“没有五颜六色的花冠，花不会吸引传粉者，也不会受精。”

【逻辑分析】根据定位句，不能受精，就影响其生长。

【选项分析】
A.文章说：花冠是接收花粉粒和花粉生长的地方，所以破坏花冠就间接阻断了授粉和制造种子。而不是暴露种子，故错误。
B.花冠与柱头是2个东西，文章未说其关系，故错误。
C.文章未提及，故错误。
D.一旦花冠被破坏，花朵不能再吸引传份昆虫，故 D 正确。

question_stem: The word “devour” in the passage is closest in meaning to
choices: tag: A
text: attack

tag: B
text: eat

tag: C
text: damage

tag: D
text: prefer
answer_key: B
explanation: 【题目翻译】单词“devour”与下列哪一个意思最相近？
A：attack，攻击
B：eat，吃
C：damage，危害
D：prefer，偏爱

【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“devour”,定位到原句“Caterpillars devour the ovaries, where the seeds are produced, and seed beetle larvae eat seeds as they burrow in developing fruits.”。

【词汇解析】：词汇“devour”的意思是“狼吞虎咽”,带入到原句中，原句的意思是“毛毛虫毁坏子房，这是生产种子的地方，在果实成熟过程中，象鼻虫的幼虫进入果实内部蚕食种子。”

【选项分析】
A：attack，攻击，不符，错误
B：eat，吃，同义替换，正确
C：damage，危害，不符，错误
D：prefer，偏爱，不符，错误

question_stem: What role does paragraph 5 play in the passage?
choices: tag: A
text: It offers various kinds of evidence for the protectionist view.

tag: B
text: It presents the study that first proved that ants benefit plants.

tag: C
text: It explains how insects find sources of nectar.

tag: D
text: It presents information that partly contradicts the protectionist view.
answer_key: A
explanation: 【题目翻译】第5段在文章中扮演什么角色？
A：它为保护主义观点提供了各种证据。

B：首先证明蚂蚁有益于植物的研究。

C：它解释了昆虫如何找到花蜜的来源。

D：它提供的信息部分与保护主义观点相矛盾。

【判定题型】：根据题目问法，题目询问 xxx 组成或构成方式/段落与段落的关系/某一段在全文中所起的作用，故判断本题为组织结构题。

【内容分析】本段主要是用实验来证明了有 ants 保护的植物可以产出更多的种子，所以最终证明了 ants 等昆虫会被植物外部花蜜吸引并且对植物进行保护。

【选项分析】
A.第五段证明了保护主义理论，对应 A 选项。选 A。
B.不是首先证明，而且也不是有益植物的研究，而是有益植物的种子生长，故错误。
C.本段主要是要证明蚂蚁对植物的保护作用，故错误。
D.并无相矛盾的部分，故错误。

question_stem: The word “vulnerable” in the passage is closest in meaning to
choices: tag: A
text: numerous

tag: B
text: harmful

tag: C
text: open to attack

tag: D
text: difficult to locate
answer_key: C
explanation: 【题目翻译】单词“vulnerable”与下列哪一个意思最相近？
A：numerous，巨大的
B：harmful，有害的
C：open to attack，开放的攻击
D：difficult to locate，难以定位

【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“vulnerable”,定位到原句“Although ants are not big enough to kill or seriously injure grasshoppers, they drive them away by nipping at their feet. Seed beetles are more vulnerable because they are much smaller than grasshoppers. ”。

【词汇解析】：词汇“vulnerable”的意思是“易受攻击的/脆弱的”,带入到原句中，原句的意思是“尽管蚂蚁不够强大，不能杀死或严重伤害草蜢，但是蚂蚁可以通过啃咬草蜢的脚驱赶它们。”

【选项分析】
A：numerous，巨大的，不符，错误
B：harmful，有害的，不符，错误
C：open to attack，开放的攻击，同义替换，正确
D：difficult to locate，难以定位，不符，错误

question_stem: According to paragraph 5, what did Bentley’s comparative study show?
choices: tag: A
text: Many more plants grew in places where ants were present than where they were absent.

tag: B
text: The ants preferred plants with low seed production to plants with high seed production.

tag: C
text: The plants occupied by ants produced many more seeds than those that were not occupied by ants.

tag: D
text: The plants that grew in places without ants were much smaller and weaker than those that grew in places where ants were present.
answer_key: C
explanation: 【题目翻译】根据第5段，Bentley 的比较研究表明了什么？
A：有蚂蚁的地方比没有蚂蚁的地方生长的植物多。
B：蚂蚁喜欢种子产量低的植物，而不是种子产量高的植物。
C：被蚂蚁占据的植物比没有被蚂蚁占据的植物产生更多的种子。
D：在没有蚂蚁的地方生长的植物比在有蚂蚁的地方生长的植物小得多，而且弱得多。

【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 5第4句，原句为“Bentley compares the seed production of six plants that grew where there were no ants with that of seventeen plants that were occupied by ants. Unprotected plants bore only 45 seeds per plant, but plants occupied by ants bore 211 seeds per plant.”，意思是“通过观察可以确定蚂蚁保护牵牛花的花朵和果实不会受到草蜢、毛毛虫和象鼻虫的联合侵袭。”

【逻辑分析】定位句：有蚂蚁保护的植物比没有蚂蚁保护的植物能产出更多的种子。

【选项分析】
A.不受蚂蚁保护的植物每株只结出45个种子，而有蚂蚁保护的植物每株结出了211个种子。所以是种子多，不是植物多，故错误。
B.文章未提到蚂蚁喜欢什么，故错误。
C.符合原文，故正确。
D.和 A 选项一样，是种子多，故错误。

question_stem: According to paragraph 5, ants defend morning glory plants from seed beetles in each of the following ways EXCEPT
choices: tag: A
text: driving adult beetles off the plants by nipping at their feet

tag: B
text: catching and eating adult beetles

tag: C
text: eating beetle eggs they find on developing fruits

tag: D
text: making it difficult for beetles to lay eggs on developing fruits
answer_key: A
explanation: 【题目翻译】根据第5段，蚂蚁通过以下每一种方式保护牵牛花植物免受种子甲虫的侵害，除了哪一个不对
A：通过咬成年甲虫的脚把它们赶走。

B：捕捉和食用成年甲虫

C：吃他们在水果发育过程中发现的甲虫蛋

D：使甲虫难以在发育中的果实上产卵。

【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“morning glory plants”,可以将出题范围锁定在 Passage5。

【选项分析】
A、Although ants are not big enough to kill or seriously injure grasshoppers, they drive them away by nipping at their feet.这里讲了 ants 可以赶走蚱蜢，而不是赶走成年的甲虫，和 A 选项内容不符，A 错，所以选 A。

B、定位 The ants prey on the adult beetles.对应 B 选项；
C、…disturb females as they lay their eggs on developing fruits, and eat many of the eggs they do manage to lay.对应 C 选项；
D、…disturb females as they lay their eggs on developing fruits, and eat many of the eggs they do manage to lay.对应 D 选项；