题目解析：
【题目翻译】第3段提到以下所有在非洲饲养牛的理由，除了哪个之外：
A牛不得不经常喝水。
B牛需要大面积优质牧草。
C牛从一个季节到下一个季节需要大量的移动。
D牛群向南扩散后，牛群得了昏睡病。
【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“raising cattle in Africa was demanding”,可以将出题范围锁定在Passage 3 的第一二句话。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.
【选项分析】
A选项：牛需要频繁地喝水。可以定位到第三段第2句话“ They required water at least every 24 hours and large tracts of grazing grass if herds of any size were to be maintained.”这句话说牛群至少每24小时就需要喝水，说明A选项符合原文，故排除。
B选项：牛群需要大片高质量的牧草。根据关键词“grazing grass”同样定位到第三段第2句，所以B选项符合原文，故排除。
C选项：从一个季节转变到下一个季节时，牛群需要移动很远的距离。定位到这句话“To acquire such land often required moving herds considerable distances, even from summer to winter pastures.”这句话表明，牛群经常需要移动相当远的距离，从夏季牧场迁移到冬季牧场。所以这里C选项符合原文，故排除。
D选项：牛群迁移到南部之后，开始患上昏睡病。但是原文中说的是，为了避免感染昏睡病，牛群迅速向南部地区迁移。所以南部是没有致病的舌蝇出没的。故D选项与原文矛盾，为正确答案。
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 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.
