2. 职称英语
  3. Vitamins are organic compounds necessary in small amounts in the diet for th

Vitamins are organic compounds necessary in small amounts in the diet for th

游客2025-04-03  31
问题     Vitamins are organic compounds necessary in small amounts in the diet for the normal growth and maintenance of life of animals, including man.
    They do not provide energy, 【C1】______do they construct or build any part of the body. They are needed for【C2】______foods into energy and body maintenance. There are thirteen or more of them, and if 【C3】______is missing a deficiency disease becomes【C4】______.
    Vitamins are similar because they are made of the same elements—usually carbon, hydrogen, oxygen, and【C5】______nitrogen. They are different【C6】______their elements are arranged differently, and each vitamin【C7】______one or more specific functions in the body.
    【C8】______enough vitamins is essential to life, although the body has no nutritional use for 【C9】______vitamins. Many people, 【C10】______, believe in being on the "safe side" and thus take extra vitamins. However, a well balanced diet will usually meet all the body’s vitamin needs. [br] 【C3】
选项 A、any
B、some
C、anything
D、something
答案 A
解析 空格所在句子是一个由and连接的并列句，前一个分句There are thirteen or moreof them中的them指的是vitamins，后一个分句是一个由if引导的条件状语从句，意为“如果……缺乏，(会出现)维生素缺乏症。”由于if引导的从句中谓语动词is是单数，因而，只能由一个表示单数意义的不定代词作为被选项。首先排除some，它一般用于肯定句，做主语时谓语动词用复数；其次anything与something泛指任何事或某些事，放入句中不符句意；any放入后相当于any of them，即“任何维生素”。注意any一般用于否定或疑问句中．做主语时，谓语动词常用单数，故选A。
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