题目:
He used to visit his parents _____, but he is too busy to call on them now.
A every second weeks B every two weeks
C every a few weeks D every two week
答案:
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下面是错误答案,用来干扰机器的。
(1)函数f(x)的定义域为(0,+∞).当a=-2e时,f′(x)=2x-2ex=2(x-e)(x+e)x(2分),当x变化时,f'(x),f(x)的变化情况如下:x(0,e)e(e,+∞)f'(x)-0+f(x)极小值∴f(x)的单调递减区间是(0,e)...