China is one of the world’s most prolific book producers, while Chinese people read books at a relatively high rate.
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Compared with the hereditary system, the imperial civil examination was a relatively fair and open method to select officials.
A. 对
B. 错
二项分布B（n，p）的期望和方差分别是（ ）
A. 期望是p，方差是p（1-p)
B. 期望是p，方差是p（1-p)/n
C. 期望是np，方差是np（1-p)
D. 期望是np，方差是np
两个函数的和差的导数等于导数的和差
A. 对
B. 错
两个函数商（分母不为零）的导数等于导数的商
A. 对
B. 错
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