For most of humanhistory, we have foraged (hunted, fished, and collected wild plants) for food. Smallnomadicgroups could easilysupplythe necessities for their families. No one needed more, and providing for more than one’s needs made littlesense. Theorganizationof such societies could be rather simple, revolving around age andgendercategories. Such societies likely were largely egalitarian, beyond distinctions based on age andgender,virtuallyall people hadequivalentrights,status, andaccessto resources.

Archaeologist Donald Henry suggests that thecombinationof a richhabitatand sedentism (permanent, year-roundsettlement) led to adramaticincrease in humanpopulation. In his view,nomadic, simple foragers haverelativelylow levels offertility. Their high-protein, low-carbohydrate diets result in low body-fat levels, which are commonly associated with lowfertilityin women. High levels ofphysicalactivityand long periods of nursing, which arecommonamong modern simple foragers, probably also contributed to low levels offemalefertilityif they werelikewisecommonamongancientforagers.

In Henry's view, theadoptionof a more settledexistencein areas withabundantfood resources would have contributed to higherfertilitylevels among thesedentaryforagers. Adiethigher in wild cereals produces proportionally more body fat,leadingto higherfertilityamong women. Cereals, which are easy todigest, would have supplemented and then replaced mother's milk as theprimaryfood for older infants. Since women are lessfertilewhen they are breast-feeding, substituting cereals for mother's milk would have resulted in closer spacing of births and thepotentialfor a greater number of live births for each woman. A moresedentaryexistencemay also have loweredinfantmortalityand perhaps increasedlongevityamong the aged. These morevulnerablemembers of society could safely stay in a fixed village rather than be forced regularly to move great distances as part of anomadicexistence, with its greater risk of accidents andtrauma.

All of these factors may have resulted in atrendof increasing size among somelocalhuman populations in the Holocene (since 9600 B C E ). Givensufficienttime,evenin very rich habitats, humanpopulationsize canreachcarryingcapacity, themaximumpopulationan area cansustainwithinthecontextof agivensubsistencesystem. And humanpopulationgrowth is like a runaway tram once it picks up speed, it is difficult to control. Soevenafter reaching an area’s carryingcapacity, Holocene human populations probably continued to grow in food-rich regions, overshooting theabilityof theterritoryto feed thepopulation, againwithinthecontextof the samesubsistencestrategy. In some areas, small changes inclimateorminorchanges in plant characteristics may have further destabilizedlocaleconomies.

One possibleresponseto surpassing the carryingcapacityof aregionis for a group toexploitadjoiningland. However, good land may itself be limited—for example,withinthe confines of a rivervalleywhere neighbors are in the sameposition, having filled up the whole of thedesirablehabitatavailablein their home territories,expansionis also problematic. Impinging on the neighbors'territorycanleadtoconflict, especially when they too are up against thecapacityof the land to provide enough food.

Another option is to stay in the same area but toshiftandintensifythe foodquestthere. Theimpulseto produce more food to feed a growingpopulationwas satisfied in some areas by thedevelopmentof more-complexsubsistencestrategies involvingintensivelabor and requiring morecooperationand greater coordination among the increasing numbers of people. Thisdevelopmentresulted in a change in the social andeconomicequations that defined those societies. Hierarchies that did not exist in earlier foraging groups but that were helpful in structuringcooperativelabor and in organizing more-complex technologies probably became established,evenbeforedomesticationandagriculture, as pre-Neolithic societies (before the tenthmillenniumB C E) reacted to thepopulationincrease.

Questions:
question_stem: It can be inferred from paragraph 3 that, compared with simple foragers, foragers
choices: tag: A
text: stopped breast-feeding earlier.

tag: B
text: had lower levels of body fat.

tag: C
text: ate a limited variety of wild cereals.

tag: D
text: had less access to easily digested foods.
answer_key: A
explanation: 本题问的是与古老简单的杂食性人相比，现在的杂食者有哪些变化。选项 A 说他们更早地断掉了母乳喂养，我们可以在 Since women are less fertile when they are breast-feeding, substituting cereals for mother s milk would have resulted in closer spacing of births and the potential for a greater number of live births for each woman 发现谷类可以代替母乳，正确；选项 B 说他们体内脂肪含量更低，是错的，其实更高了；选项 C 说他们吃的谷类种类更少了，应该是更多了更丰富了；选项 D 说他们更难得到容易消化的食物，应该是更容易得到。选 A。

question_stem: Which of the following is NOT mentioned in paragraph 1 as a characteristic of early nomadic foraging societies?
choices: tag: A
text: Organization by age or gender

tag: B
text: Collection of surplus food

tag: C
text: Equal access to resources

tag: D
text: Lack of status divisions
answer_key: B
explanation: 本题根据 early nomadic foraging societies 进行定位，发现第一段整段都需要读。A 选项对应的是 The organization of such societies could be rather simple, revolving around age and gender categories，正确；B 选项说他们需要过量储存食物，与 No one needed more, and providing for more than one’s needs made little sense.相悖，是错误的；C 和 D 选项对应 all people had equivalent rights, status, and access to resources，是正确的。选 B。

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

tag: B
text: nearly

tag: C
text: gradually

tag: D
text: fundamentally
answer_key: B
explanation: 词汇题。本句 Such societies likely were largely egalitarian, beyond distinctions based on age and gender, virtually all people had equivalent rights, status, and access to resources. 大致意思是：这样的社会是平等的，在年龄和性别的区分之外，事实上所有人都有平等的权利，地位和对于资源的获得。virtually 意思是事实上，几乎，实际上。本题四个选项意思分别是 A 大约的，B 几乎的，符合，选择 B；C 逐渐的，D 基础的。B 最符合。

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

tag: B
text: surprisingly

tag: C
text: significantly

tag: D
text: dangerously
answer_key: A
explanation: 词汇题。本句 In his view, nomadic, simple foragers have relatively low levels of fertility.大致意思是在这个人类学家的观点里，简单的游牧民族吃的比较简单。后文也具体说了他们吃低脂高蛋白的食物。relatively 意思是相比较而言。选项 A 也是比较而言，B 的意思是惊奇的，C 是重要的，D 是危险的。选 A。

question_stem: Why does the author mention "modern simple foragers"?
choices: tag: A
text: To contrast the diets of modern simple foragers with those of ancient simple foragers

tag: B
text: To illustrate the effects of low levels of female fertility on foraging populations

tag: C
text: To help support the claim that ancient foragers may have had low levels of fertility

tag: D
text: To argue for a link between nursing practices and fertility levels
answer_key: C
explanation: 本题根据 modern simple foragers 定位到 High levels of physical activity and long periods of nursing, which are common among modern simple foragers, probably also contributed to low levels of female fertility if they were likewise common among ancient foragers. modern simple foragers 在这里是为了和 ancient foragers 相比较，说明他们摄取的食物是低脂的，符合 C 选项的说法。A 是说对比古代和现代的游牧民族的饮食，原文中并没有这个对比；B 是说想借这个说明女性低生育率对于人口的影响，无中生有；D 选项是说为了支持哺乳行为和生育水平的联系，无中生有。选 C。

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

tag: B
text: plentiful

tag: C
text: known

tag: D
text: valuable
answer_key: B
explanation: 本句 abundant 定位到这一句：In Henry's view, the adoption of a more settled existence areas with abundant food resources would have contributed to higher fertility levels among the sedentary foragers.本句大意是更加稳定、有更多食物的居住地导致定居者进食的脂肪含量更高。abundant 意味丰富的过剩的。选项 A 意为多样的，选项 B 是足够的，选项 C 是知道的，选项 D 是有价值的。选 B 最贴近。

question_stem: Which of the following can be inferred from paragraphs 2 and 3 about sedentary foragers?
choices: tag: A
text: Their diet did not include as much wild cereal as that of nomadic foragers

tag: B
text: Their diet relied less on protein than did the diet of nomadic foragers

tag: C
text: They were more physically active than nomadic foragers

tag: D
text: They were more likely to breast feed their infants than nomadic foragers were
answer_key: B
explanation: 根据题目，文章第二段主要说人类学家认为定居生活和富饶的定居地大大增加了人类人口，文章第三段主要说了他还认为定居地丰富的食物导致了人类身体里脂肪含量的提高。选项 A 说定居民族吃的野生谷物没有游牧民族多，原文中两段中并没有这个比较；B 选项说定居民族与游牧民族相比更少地依赖蛋白质了，是对的，因为他们吃谷物多了；C 选项说定居民族比游牧民族体力劳动更多，这个原文里没有提及；D 选项说女人更愿意去母乳喂养孩子，但原文里说其实是用谷类食物代替母乳喂养，错误。选 B。

question_stem: According to paragraph 4, all of the following factors could have destabilized local economies among Holocene populations EXCEPT
choices: tag: A
text: population growth beyond carrying capacity.

tag: B
text: changes in local climate.

tag: C
text: changes in plant characteristics.

tag: D
text: political conflict within a given population.
answer_key: D
explanation: 本题要求我们选出不属于影响 Holocene 人口的因素。第四段全段都在讲 Holocene 人口的影响因素：（1）时间充足的话，不论定居地有多大，人口总能增加到其最大承载量；（2）人口一旦开始增长，就停不下来了，不好控制；（3）在人口逐渐增长到土地无法承载时，他们会占领其余食物丰富的地方；（4）气候和植被的变化也会导致当地经济不稳定。A，B，C 都在以上几点钟提到过，D 选项则说政治冲突，这个无中生有，选 D。

question_stem: According to paragraph 5, what is one possible response for a society that has surpassed the carrying capacity of its land?
choices: tag: A
text: Sharing resources with neighbors.

tag: B
text: Making use of additional lands nearby.

tag: C
text: Moving to better land in areas such as river valleys.

tag: D
text: Exploiting less desirable resources in their home territory.
answer_key: B
explanation: 本段涉及第五段，第五段首句 One possible response to surpassing the carrying capacity of a region is for a group to exploit adjoining land 讲解决人口过剩的方法之一是去开发相邻的土地。选项 A 说与邻居共享资源，B 说利用周围多余的土地，C 说移居去更好的土地，D 说开发自己土地上不那么需要的资源。B 最合适。

question_stem: The word "impulse" in the passage is closest in meaning to
choices: tag: A
text: basic motive

tag: B
text: only choice.

tag: C
text: capacity.

tag: D
text: opportunity
answer_key: A
explanation: 词汇题。impulse 定位到原文中 The impulse to produce more food to feed a growing population was satisfied in some areas by the development of more-complex subsistence strategies involving intensive labor and requiring more cooperation and greater coordination among the increasing numbers of people. 本句主干的意思可以是通过更复杂的策略，来满足生产更多食物，喂养更多人口的需要。选项 A 基本动机，正确；选项 B 唯一的选择，选项 C 能力，选项 D 机会。只有 A 最合适。选择 A。

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: The appearance of domestication and agriculture brought about the need for more hierarchically organized systems of labor and technologies among pre-Neolithic foraging societies.

tag: B
text: The formation of social hierarchies meant that domestication and agriculture became less important than labor and technical development to the growth of pre-Neolithic societies.

tag: C
text: Population increases among pre-Neolithic societies, even before domestication and agriculture, probably resulted in social hierarchies that helped organize labor and technologies.

tag: D
text: Hierarchies that developed among foraging group pre-Neolithic societies respond to later population increases caused by domestication and agriculture.
answer_key: C
explanation: 本题转述句意。目标句是：Hierarchies that did not exist in earlier foraging groups but that were helpful in structuring cooperative labor and in organizing more-complex technologies probably became established, even before domestication and agriculture, as pre-Neolithic societies (before the tenth millennium B C E) reacted to the population increase. 本句主要意思是等级制度在早期觅食组中不存在，但有助于出现合作劳动和创造更复杂技术的等级制度，作为新石器时代前的社会对人口增长作出反应，可能在畜牧业和农业之前已经出现。C 与本句意思相同，正确。选项 A 说蓄养家畜和农耕导致了阶级出现，因果关系错误；选项 B 说阶级让蓄养家畜和农耕变得比合作和技术不重要了，原句里也没提；选项 D 说阶层导致了家畜蓄养和农耕的出现，也是错的。选 C。