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  3. Nowadays it is understood that a diet, which contains nothing harmful may yet result in serious disease if certain important de

Nowadays it is understood that a diet, which contains nothing harmful may yet result in serious disease if certain important de

admin2010-05-26  60
问题      Nowadays it is understood that a diet, which contains nothing harmful may yet result in serious disease  if certain important dements are missing. These elements are called "vitamins". Quite a number of such substances are known and they are given letters to identify them, A, B, C, D, and so on. Different diseases are associated with deficiencies of particular vitamins. The vitamins necessary for a healthy body are normally supplied by a good mixed diet, including a variety of fruit and green vegetables, h is only when people try to live on a very restricted diet, say during extended periods of religious fasting, or when trying to lose weight, that it is necessary to make special provision to supply the missing vitamins.
    One example of the dangers of a restricted diet may be seen in the disease known as beriberi(脚气病), which used to afflict large numbers of Eastern peoples who lived mainly on rice. In the early years of this century, a Dutch scientist called Eijkman was trying to discover the cause of beriberi. At first he thought it was transmitted by a germ. He was working in a Japanese hospital, where the patients were fed on rice which had had the outer husk removed from the grain. It was thought this would be easier for weak, sick people to digest. Eijkman thought his germ theory was confirmed when he noticed, the chicken in the hospital yard, which were fed on scraps from the patients’ plates, were also showing signs of the disease. He then tried to isolate the germ fie thought was causing the disease, but his experiments were interrupted by a hospital official, who claimed that the huskless rice, even though left over by the patients,  was too good for chickens. It should be recooked and the chickens fed on cheap, coarse rice with file outer covering still on the grain. Eijkman noticed that the chickens began to recover on the new diet. He began to consider the possibility that eating unmilled rice somehow prevented or cured beriberi—even that a lack of some ingredient in the husk might be the cause of the disease.
    Indeed this was the case. The element needed to prevent beriberi was shortly afterwards isolated from rice husk and is now known as vitamin B. The milled rice, though more expensive, was in fact perpetuating the disease the hospital was trying to cure. Nowadays, this terrible disease is much less common;  thanks to our knowledge of vitamins.
The ingredient missing from milled rice______.
选项 A、was vitamin B
B、did not affected the chickens
C、was named the Eijkman vitamin
D、has never been accurately identified
答案A
解析 细节题。本题问的是：碾过的大米中缺乏的成分是______。仔细分析文章中的例子可知，医院里的病人和鸡因为吃碾过的大米而得了脚气病——一种由于缺乏维生素B而引发的疾病；而改吃带壳的糙米后，疾病的症状就消失了。这说明碾过的大米中缺乏维生素 B，故选A 。
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