The Sahara is a highlydiverse,albeitdry,regionthat has undergonemajorclimaticchanges since 10,000 B.C. As recently as 6,000 B.C. the southernfrontierof thedesertwas far to the north of where it is now, whilesemiaridgrassland andshallowfreshwater lakes covered much of what are nowaridplains. This was alandscapewhereantelopeof all kinds abounded----along with Bos primigenius, a kind of oxen that has becomeextinct. The areas that are nowdesertwere, like allaridregions, verysusceptibleto cycles of higher andlowerlevels ofrainfall, resulting inmajor, sudden changes in distributions of plants and animals. The people who hunted thesparsedesertanimals responded todroughtby managing the wild resources they hunted and gathered, especially wild oxen, which had to haveregularwater supplies tosurvive.

Evenbefore thedrought, the Sahara was never well watered. Both humans and animals wereconstantlyon the move, in search of food andreliablewater supplies. Under these circumstances, archaeologist Andrew Smith believes, the small herds of Bos primigenius in thedesertbecame smaller, more closely knitbreedingunits as thedroughttook hold. The beasts were more disciplined, so that it was easier for hunters topredicttheir habits, andcaptureanimals at will. At the same time, bothcattleand humans were more confined in their movements, staying much closer topermanentwater supplies for long periods of time. As a result,cattleand humans came into closeassociation.

Smith believes that the hunters were wellawareof the more disciplined ways in which theirpreybehaved. Insteadof following thecattleon theirannualmigrations, the hunters began to prevent theherdfrom moving from onespotto another. At first, they controlled the movement of theherdwhile ensuring continuance of their meatdiet. But soon they also gainedgeneticcontrol of the animals, which led to rapidphysicalchanges in theherd. South African farmers whomaintainherds of wild eland (large African antelopes with short, twisted horns)reportthat theoffspringsoondiminishin size, unless wild bulls are introducedconstantlyfrom outside. The same effects of inbreeding may have occurred in controlledcattlepopulations, with someadditional, and perhaps unrecognized, advantages. The newlydomesticatedanimals behaved better, were easier to control, and may have enjoyed a higher birthrate, which in turn yielded greater milk supplies. We know from rock paintings deep in the Sahara that the herders were soon selectingbreedinganimals to produceoffspringwith differenthornshapes andhidecolors.

It is still unclear whetherdomesticatedcattlewere tamed independently in northern Africa or introduced to thecontinentfrom southwest Asia. Whatever thesourceof theoriginaltamed herds might have been, it seemsentirelylikely that much the sameprocessof juxtaposition (living side by side) and control occurred in both southwest Asia and northern Africa, andevenin Europe, among peoples who had anintimateknowledge of thebehaviorof wildcattle. The experiments withdomesticationprobably occurred in many places, as people living in ever-drier environmentscastaround for morepredictablefood supplies.

Thecattleherders had only a few possessions: unsophisticated pots and polished adzes. They also hunted with bow andarrow. The Saharan people left aremarkablerecordof their lives painted on the walls of caves deep in thedesert. Theirartisticendeavors have been preserved in paintings of wild animals,cattle, goats, humans, and scenes of daily life thatextendback perhaps to 5,000 B.C.. Thewidespreaddistributionofpastoralsites of this period suggests that the Saharans ranged their herds over widely separated summer and wintergrazinggrounds.

About 3,500 B.C.,climaticconditions again deteriorated. The Sahara slowly became drier and lakes vanished. On the other hand,rainfallincreased in theinteriorof western Africa, and the northern limit of the tsetse fly, aninsectfataltocattle, moved south. So the herders shifted south, following themajorriver systems into savanna regions. By this time, the Saharan people were probably usingdomesticcrops, experimenting with such summerrainfallcrops as sorghum and millet as they move out of areas where they could grow wheat, barley, and otherMediterraneancrops.

Questions:
question_stem: According to paragraph 1, what was true of the Sahara region around 6,000 B.C.?
choices: tag: A
text: Much less of it was desert than is now the case.

tag: B
text: Most areas that are now grassland were covered by shallow lakes.

tag: C
text: It had just undergone a major climatic change.

tag: D
text: Wild oxen and antelopes lived in separate parts of the region.
answer_key: A
explanation: A 原文写到“在公元前六千年左右，在沙漠的南边界，远离北边的地方现在是干旱的平原，当时这里是各种羚羊和原始牛都很丰富的山水画般的地方”那么也就是说那时候那个地方还不是沙漠。所以 A，当时沙漠要比现在少，正确。B 现在没有 grassland。C 并没说这个改变是在公元前6000年发生的。D 通过“along with”可以知道这两种动物是生活在一起的。

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

tag: B
text: almost

tag: C
text: though

tag: D
text: rather
answer_key: C
explanation: C albeit: 虽然，即使。对应 C 选项 though（即使）。对应原文 The Sahara is a highly diverse, albeit dry, region that has undergone major climatic changes since 10,000 B.C.通过原文 albeit 前后两个词可以推出转折意义，前面是多样性的，后面是干燥的，两者有褒贬对比，所以选 C。

question_stem: According to paragraph 1, which of the following is true of all arid regions?
choices: tag: A
text: They include at least some freshwater lakes.

tag: B
text: They have similar distributions of plants and animals.

tag: C
text: They are greatly affected by changes in the amount of rain they receive.

tag: D
text: They have frequent droughts that make it difficult to manage the wild resources.
answer_key: C
explanation: C 根据 all arid region 定位（红色标出句）选项 A 错误，原文没说。B，原文虽然提到了 distribution of plants，但是并没说所有的干燥地区这一点都是相似的。C 正确，原文说 very susceptible to higher and lower levels of rainfall。D 错误，最后一句说人们因此而开始 manage resources。

question_stem: Paragraph 2 supports which of the following ideas about wild oxen in the Sahara region after the drought took hold?
choices: tag: A
text: They traveled in smaller herds.

tag: B
text: They were harder for hunters to capture.

tag: C
text: They tended to be significantly smaller in size.

tag: D
text: They moved along less predictable routes.
answer_key: A
explanation: A 用 oxen 定位，发现没有出现，但是对应原文的 beasts 和 cattle, 对应文章地三句，第四句： The beasts were more disciplined, so that it was easier for hunters to predict their habits, and capture animals at will. At the same time, both cattle and humans were more confined in their movements, staying much closer to permanent water supplies for long periods of time.根据原文说：牲畜们更加驯化，习性更加好预测，更容易抓，并且动物和人类在移动中更加受限，也就是指他们群体更小了，对应 A 选项。所以 B,D 错误，C 原文没提到，只说其群体变小。

question_stem: According to paragraph 2, what was it that brought cattle and humans into close association?
choices: tag: A
text: The development of smaller breeding units within hers.

tag: B
text: Cattle and humans staying close to permanent water supplies for long period of time.

tag: C
text: The development of greater discipline among cattle.

tag: D
text: Cattle and humans constangly on the move searching for food and reliable water supplies.
answer_key: B
explanation: B 根据 close association 定位到最后一句,但这句说 as a result，那么原因就在前面一句： At the same time, both cattle and humans were more confined in their movements, staying much closer to permanent water supplies for long periods of time.前一句说 cattle human 都离水源更近了，所以完美的对应了 B。ACD 选项不是导致这个结果的原因。

question_stem: Why does the author mention the “rock paintings deep in the Sahara”?
choices: tag: A
text: To help explain why the hunters wanted to control the herds.

tag: B
text: To provide support for the idea that the herders soon gained genetic control of the cattle

tag: C
text: To show that the herders had artistic as well as practical abilities

tag: D
text: To argue that the herders soon began to value their cattle for more than food.
answer_key: B
explanation: B 这个例子之前一直在说 herders gained genetic control 和其影响。然后给出这个例子,后面的内容也在说放牧人是怎样进行基因控制的.所以应该选 B。

question_stem: According to paragraph 3, all of the following statements were true of newly domesticated animals EXCEPT
choices: tag: A
text: They were controlled more easily by the farmers.

tag: B
text: They produced a larger number of offspring.

tag: C
text: They produce more milk.

tag: D
text: They were larger in size.
answer_key: D
explanation: D 根据 domesticated animals 定位到这一段最后两句话： The newly domesticated animals behaved better, were easier to control, and may have enjoyed a higher birth rate, which in turn yielded greater milk supplies. We know from rock paintings deep in the Sahara that the herders were soon selecting breeding animals to produce offspring with different horn shapes and hide colors. A 选项的 controlled more easily 和对应原文的 easier to control 对应，不选；B 选项的 a larger number of offspring 和原文的 a higher birth rate 对应，不选；C 选项的 more milk 和原文的 greater milk supplies 对应，不选；D 选项的 larger in size 和原文倒数第四句话的 offspring soon diminish in size 相反，所以错误，选 D。

question_stem: which of the sentences below best expresses the essential information in the highlighted sentence in the passage paragraph 4? Incorrect choices change the meaning in important ways or leave out essential information.
choices: tag: A
text: Regardless of where the first tamed herds came from, people tried to control them by living in juxtaposition with them.

tag: B
text: Regardless of where the first tamed herds came from, they resulted from the same process of juxtaposition and control by people who understood the behavior of wild cattle.

tag: C
text: People who had an intimate knowledge of the behavior of wild cattle moved closer together to cooperate in taming the herd, regardless of where they found them.

tag: D
text: The process of taming herds was certainly the same in southwest Asia, northern Africa, and Europe because people knew a lot about the behavior of wild cattle, regardless of where they lived.
answer_key: B
explanation: B 原句的主要逻辑是让步状语从句，这主干内容是,不管驯化动物从哪起源的,最后在不同的地区得到的都是同样的方法: juxtaposition 和 control。根据以上信息对选项进行排除：A:前半句没问题，后半句和原文关系不符；B:正确,包括了所有主干部分；C:完全和原文说的不是一回事儿；D:和原文逻辑关系矛盾，原文并没有因果关系。

question_stem: According to paragraph 5, each of the following was true about the early Saharan people EXCEPT
choices: tag: A
text: They had few possessions apart from cattle.

tag: B
text: After about 5,000 , they lived primarily in caves that were located deep in the desert.

tag: C
text: Between the summer and winter seasons, they moved their herds over long distances.

tag: D
text: They painted animals and scenes of daily life on the walls of caves.
answer_key: B
explanation: B    A 对应第一句: The cattle herders had only a few possessions: unsophisticated pots and polished adzes.除了牛,他们就只有住所和斧头。C 对应最后一句： The widespread distribution of pastoral sites of this period suggests that the Saharans ranged their herd over widely separated summer and winter grazing grounds. D 对应第三句： Their artistic endeavors have been preserved in paintings of wild animals, cattle, goats, humans, and scenes of daily life that extend back perhaps to 5000 B.C B 也对应到第三句，原文虽然说到他们在沙漠深处的洞穴里画画了,但是没说他们住那。所以不对,选 B。

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

tag: B
text: styles

tag: C
text: scenes

tag: D
text: efforts
answer_key: D
explanation: D  endeavor: 努力, 尽力。A 是方法;B 风格;C 景象;D 努力。所以 D 最贴切。对应原文 Their artistic endeavors have been preserved in paintings of wild animals, cattle, goats, humans, and scenes of daily life that extend back perhaps to 5000 B.C.从文章可以推测。之前在描述他们的生活场景,财产,打猎。然后说他们画画。这里问的是记录了什么，那么应该是他们之前做出的努力~。别的单词带入后都解释不通。

question_stem: The word “deteriorated” in the passage is closest in meaning to
choices: tag: A
text: became unstable

tag: B
text: caused hardship

tag: C
text: changed completely

tag: D
text: got worse
answer_key: D
explanation: D deteriorate: 恶化，变坏。A 是不稳定,B 是困苦,C 是完全改变, D 是变坏了、变糟了，所以 D 是正确选项。对应原文 About 3500 B.C., climatic conditions again deteriorated. The Sahara slowly became direr and lakes vanished.通过这个词后面的一句话对撒哈拉的描写可以看出都是负面发展：更干燥，湖也消失了。而 deteriorate 要和这样的变化呼应。ABC 均不能很好地体现下文语境。只有 D 最合适。

question_stem: According to paragraph 6, what allowed the herders to shift south into the savanna regions after about 3,500 B.C.?
choices: tag: A
text: They could easily grow Mediterranean crops in those regions.

tag: B
text: They could more easily domesticated sorghum and millet in those regions.

tag: C
text: The tsetse fly was no longer a problem in those regions.

tag: D
text: The river systems in those regions provided reliable sources of water in the summer.
answer_key: C
explanation: C  根据 shift south 和 savanna region 定位信息,这句话开头出现 So，那证明往前一句就是原因： On the other hand, rainfall increased in the interior of western Africa, and the northern limit of the tsetse fly, an insect fatal to cattle, moved south.前一句说西部降水变多了,并且 northern limit of the tsetse fly moved south，所以牛群也 move south，对应了 C 选项。D 可能是个迷惑选项，但是按原文的意思，river 只是牛迁徙的路径"following"，但并不是原因.