【单选题】【消耗次数：1】
等差数列{an}的首项为1，公差不为0.若a2，a3，a6成等比数列，则{an}前6项的和为( )
①
-3
②
-24
③
3
④
8
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【简答题】
设{an}是公比为 q 的等比数列，且a1，a3，a2成等差数列．(1)求q的值；(2)设{bn}是以2为首项，q为公差的等差数列，其前n项和为Sn，当n≥2时，比较Sn与bn的大小，并说明理由．
【单选题】
等差数列0，-3，-6，······的通项公式是( )
①
<img src="20190809/1565314218197257.png" title="1565314218197257.png" alt="图片5.png"/>
②
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<img src="20190809/1565314247141241.png" title="1565314247141241.png" alt="图片7.png"/>
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<img src="20190809/1565314264699167.png" title="1565314264699167.png" alt="图片8.png"/>
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关于等差数列的概念，描述正确的是哪一项（ ）
①
一般地，如果一个数列，每一项与它的前一项的差都等于常数，那么这个数列叫等差数列
②
一般地，如果一个数列，从第二项起，每一项与它的前一项的差都等于常数，那么这个数列叫等差数列
③
一般地，如果一个数列，从第二项起，每一项与它的前一项的差都等于同一个常数，那么这个数列叫等差数列
④
一般地，如果一个数列，每一项与它的前一项的差都等于同一个常数，那么这个数列叫等差数列
【简答题】
已知方程(x2－2x＋m)(x2－2x＋n)＝0的四个根组成一个首项为1/4的等差数列，求｜m－n｜的值．
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overlooked
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opened
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The car ran over the child, but by a _____ he was unhurt.
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wonder
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marvel
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miracle
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You will probably _____ your team’s chance to win because you seem to have such a great ______them.
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affect; influence
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effect; influence
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Yes, of course.
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No, thanks.
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I was satisfied with her explanation, ______.
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so my classmates were
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so were my classmates
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so my classmates did
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A kind teacher always takes a very _______ attitude when correcting students’ mistakes.
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negative
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