皮皮学，免费搜题
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【单选题】
成人缺乏维生素D时易引起A.
夜盲症；
B.
软骨病；
C.
佝偻病；
D.
皮肤癌；
E.
以上都不是。
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【简答题】ization is a general trend now and there are merits and demerits. In facing of the potential problems emerged,your suggestions are appreciated. Write a composition of about 200 words on the follo...
【单选题】有一台三相异步电动机,电源频率为50Hz,额定转速为950r/min,考虑机械特性为直线,则半载运行速度为 。
A.
1000 r/min
B.
975 r/min
C.
500 r/min
D.
475 r/min
【单选题】What does the author mean by the word 'progress' in this passage?
A.
Urbanization.
B.
Economic growth.
C.
Cultural development.
D.
Increase of population.
【单选题】Which of the following does NOT show the results of urbanization?
A.
It enables citizens to think and work creatively.
B.
Manufacturing productivity has been improved.
C.
It encourages more environment friendly living style.
D.
It attracts people and enables them to collaborate.
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