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“，正名芡实，因肇庆所产之芡实颗粒大、药力强，故名。”某科研所为进一步改良，为此对的两个品种（分别称为品种A和品种B）进行试验．选取两大片水塘，每大片水塘分成n小片水塘，在总共2n小片水塘中，随机选n小片水塘种植品种A，另外n小片水塘种植B． （1）假设n=4，在第一大片水塘中，种植品种A的小片水塘的数目记为 ，求 的分布列和数学期望； （2）试验时每大片水塘分成8小片，即n=8，试验结束后得到品种A和品种B在每个小片水塘上的每亩产量（单位：kg/亩）如下表： 号码 1 2 3 4 5 6 7 8 品种A 101 97 92 103 91 100 110 106 品种B 115 107 112 108 111 120 110 113 分别求品种A和品种B的每亩产量的样本平均数和样本方差；根据试验结果，你认为应该种植哪一品种？
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【简答题】糖原、淀粉和纤维素分子中都有一个还原端，所以它们都有还原性。( )
【单选题】So does an attitude which sees the public only in terms of large, malleable numbers—as impersonally as does the clattering subway turnstile beneath the office towers.
A.
innumerable
B.
rigid
C.
flexible
D.
inoperable
【单选题】Why does Amina have a very positive attitude when it comes to learning foreign languages?
A.
Because she has many Chinese friends that can help her.
B.
Because she is probably a quick learner, so she has an advantage over people like Alex.
C.
Because she comes from Morocco, a country where people speak different languages so she can learn Chinese faster.
【简答题】1) What are the so-called “odyssey years”? 2) Why does the author say that the odyssey years are an unavoidable stage in reaching hood? 3) How do some young people in their odyssey years react to...
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