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问题 单项选择题

下列关于转贴现的说法错误的是（）。

A.银行承兑汇票转贴现的最长期限是6个月

B.转贴现的方式包括买断、卖断、买入回购和卖出回购

C.转贴现的票据必须是未到期的票据

D.转贴现的票据可以使用未经背书的票据

答案

参考答案：D

单项选择题

About fifty years ago, plant physiologists set out to grow roots by themselves in solutions in laboratory flasks. The scientists found that the nutrition of isolated roots was quite simple. They required sugar and the usual minerals and vitamins. However, they did not require organic nitrogen compounds. These roots got along fine on mineral inorganic nitrogen. Roots are capable of making their own proteins and other organic compounds. These activities by roots require energy, of course. The process of respiration uses sugar to make the high energy compound ATP, which drives the biochemical reactions. Respiration also requires oxygen. Highly active roots require a good deal of oxygen.The study of isolated roots has provided an understanding of the relationship between shoots and roots in intact plants. The leaves of the shoots provide the roots with sugar and vitamins, and the roots provide the shoots with water and minerals. In addition, roots can provide the shoots with organic nitrogen compounds. This comes in handy for the growth of buds in the early spring when leaves are not yet functioning. Once leaves begin photosynthesizing, they produce protein, but only mature leaves can "export" protein to the rest of the plant in the form of amino acids.

What is the main topic of the passage

A．The relationship between a plant’s roots and its shoots.

B．What can be learned by growing roots in isolation.

C．How plants can be grown without roots.

D．What elements are necessary for the growth of plants.
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单项选择题

以下关于CMT描述错误的是（）

A.CMT是遗传性周围神经病最常见类型.

B.是遗传性运动感觉性神经病

C.多为常染色体隐性遗传

D.双下肢呈"鹤腿"状

E.弓形足
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