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【单选题】
1943年，美国科学家艾弗里和他的同事，从S型活细菌中提取了DNA、蛋白质和多糖等物质分别加入到培养了R型细菌的培养基中，结果发现只有加入DNA，R型细菌才能转化成S型细菌，而加入蛋白质.多糖等物质的培养基中，R型细菌不能发生这种变化.这一现象能说明的是（） ①S型细菌的性状是由DNA决定的 ②在转化过程中，S型细菌的DNA可能进入到了R型细菌细胞中 ③DNA是遗传物质 ④蛋白质和多糖在该转化实验中，起了对照作用A.
①④
B.
②③
C.
①②③
D.
①②③④
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举一反三
【单选题】It can be inferred from the passage that the author would be most likely to agree with which of the following statements about the role of criticism?
A.
Its prime office should be to make our enjoyment of the things that feed the mind as conscious as possible.
B.
It should be a disinterested endeavor to learn and propagate the best that is known and thought in the world.
C.
It should enable us to go beyond personal prejudice to appreciate the virtues of works antipathetic to our own tastes.
D.
It should dwell upon excellencies rather than imperfections, ignoring such deficiencies as irrelevant.
E.
It should strive both to purify literature and to elevate the literary standards of the reading public.
【简答题】合会这种借贷形式不完全基于信用，依赖抵押品和担保。()
【简答题】10110B=( )D 232O=( )D 232H=( )D
【简答题】常用的计算机网络硬件有哪些?
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