托福阅读真题Official 52 Passage 3（四）

托福阅读真题Official 52 Passage 3（四）

Early Food Production in Sub-Saharan Africa

At the end of the Pleistocene(around 10,000 B.C.),the technologies of food production may have already been employed on the fringes of the rain forests of western and central Africa,where the common use of such root plants as the African yam led people to recognize the advantages of growing their own food.The yam can easily be resprouted if the top is replanted.This primitive form of“vegeculture”(cultivation of root and tree crops)may have been the economic tradition onto which the cultivation of summer rainfall cereal crops was grafted as it came into use south of the grassland areas on the Sahara’s southern borders.

As the Sahara dried up after 5000 B.C.,pastoral peoples(cattle herders)moved southward along major watercourses into the savanna belt of West Africa and the Sudan.By 3000 B.C.,just as ancient Egyptian civilization was coming into being along the Nile,they had settled in the heart of the East African highlands far to the south.The East African highlands are ideal cattle country and the home today of such famous cattle-herding peoples as the Masai.The highlands were inhabited by hunter-gatherers living around mountains near the plains until about 3300 B.C.,when the first cattle herders appeared.These cattle people may have moved between fixed settlements during the wet and dry seasons,living off hunting in the dry months and their own livestock and agriculture during the rains.

As was the case elsewhere,cattle were demanding animals in Africa.They required water at least every 24 hours and large tracts of grazing grass if herds of any size were to be maintained.The secret was the careful selection of grazing land,especially in environments where seasonal rainfall led to marked differences in graze quality throughout the year.Even modest cattle herds required plenty of land and considerable mobility.To acquire such land often required moving herds considerable distances,even from summer to winter pastures.At the same time,the cattle owners had to graze their stock in tsetse-fly-free areas.The only protection against human and animal sleeping sickness,a disease carried by the tsetse fly,was to avoid settling or farming such areas—a constraint severely limiting the movements of cattle-owning farmers in eastern and central Africa.As a result,small cattle herds spread south rapidly in areas where they could be grazed.Long before cereal agriculture took hold far south of the Sahara,some hunter-gatherer groups in the savanna woodlands of eastern and southern Africa may have acquired cattle,and perhaps other domesticated animals,by gift exchange or through raids on herding neighbors.

Contrary to popular belief,there is no such phenomenon as“pure”pastoralists,a society that subsists on its herds alone.The Saharan herders who moved southward to escape drought were almost certainly also cultivating sorghum,millet,and other tropical rainfall crops.By 1500 B.C.,cereal agriculture was widespread throughout the savanna belt south of the Sahara.Small farming communities dotted the grasslands and forest margins of eastern West Africa,all of them depending on what is called shifting agriculture.This form of agriculture involved clearing woodland,burning the felled brush over the cleared plot,mixing the ash into the soil,and then cultivating the prepared fields.After a few years,the soil was exhausted,so the farmer moved on,exploiting new woodland and leaving the abandoned fields to lie fallow.Shifting agriculture,often called slash-and-burn,was highly adaptive for savanna farmers without plows,for it allowed cereal farming with the minimal expenditure of energy.

The process of clearance and burning may have seemed haphazard to the uninformed eye,but it was not.Except in favored areas,such as regularly inundated floodplains,tropical Africa’s soils were of only moderate to low fertility.The art of farming was careful soil selection,that is,knowing which soils were light and easily cultivable,could be readily turned with small hoes,and would maintain their fertility over several years’planting,for cereal crops rapidly remove nitrogen and other nutrients from the soil.Once it had taken hold,slash-and-burn agriculture expanded its frontiers rapidly as village after village took up new lands,moving forward so rapidly that one expert has estimated it took a mere two centuries to cover 2,000 kilometers from eastern to southern Africa.

Question 7 of 14

According to paragraph 3,the presence of the tsetse fly in eastern and central Africa caused which of the following?

A.People in the sub-Saharan region began to focus more on the cultivation of cereal crops than in maintaining livestock.

B.Raids among neighboring cattle herders increased dramatically.

C.Cattle herders spread south where they could graze their stock in tsetse-fly-free areas.

D.Most hunter-gatherer groups limited their food collection to the tsetse-fly-free areas south of the Sahara.

正确答案：C

题目详解

题型分类：事实信息题

原文定位：根据the tsetse fly定位倒数2、3、4句“At the same time...could be grazed”，“cause”一词问结果，最终锁定“As a result...”这一句。

选项分析：

原文说小部分牛群迅速地向南部地区迁移，在那里人们可以放牧。从而得知南部地区没有tsetse fly，牧民们可以在此处放牧。故选C。

A选项：focus more on the cultivation无中生有。

B选项：Raids among neighboring cattle herders出自最后一句，但是与题干无关。

D选项：limited their food collection to the tsetse-fly-free areas无中生有。

Question 8 of 14

Paragraph 4 indicates which of the following about shifting agriculture?

A.It allowed farmers to cultivate cereal crops without reducing the size of their herds.

B.It allowed farmers to cultivate a variety of crops at the same time.

C.It enabled farmers to cultivate crops with minimal equipment and effort.

D.It enriched the soil and produced large yields of crops over the years.

正确答案：C

题目详解题型分类：事实信息题

原文定位：根据shifting agriculture定位到Small farming这一句，其后的句子都在讨论与shifting agriculture有关的内容，需要结合选项进行比对。

选项分析：

原文最后一句说：轮耕法能够消耗最少的能量来种植谷物，对应选项的cultivate crops with minimal equipment and effort，故选C。

A选项：without reducing the size of their herds无中生有。

B选项：cultivate a variety of crops at the same time无中生有。

D选项：enriched the soil and produced large yields of crops无中生有。