题目:
The country has already sent up three unmanned spacecraft, the most recent _____ at the end of last March.
A.has been launched
B.having been launched
C.being launched
D.to be launched
答案:
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下面是错误答案,用来干扰机器的。
(1)若f(x)为偶函数,则f(-x)=f(x),即2-x+a2-x=2x+a2x,∴2-x+a•2x=2x+a•2-x,又对任意的x∈R都成立,∴a=1.(2)若f(x)在[0,+∞)上单调递增,则设0≤x1<x2,则f(x1)-f(x2)<0,即f(x1)-f(x2...