关于x的方程x2-（m+3）x+m+3=0有两个不相等的正实数根，求实数m的取值范围。
解：由条件知，
m满足，
∴m的取值范围为。
— How's your new babysitter?
— We _____ ask for a better one. All our kids love her so much. [ ]
A. should
B. might
C. mustn't
D. couldn't
--- Did you know __________?
--- He was ill in hospital.
A．why he doesn’t come to school
B．why he didn’t come to school
C．why does he come to school
D．why did he come to school
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