区域划分应综合考虑（）和（）等因素综合考虑。
参考答案：无线传播环境因素；业务分布
Where does a fish live? [ ]
A. In a forest.
B. In a river.
C. In a hole.
D. In a tree.
若2x+3y-4=0，求9x-1•27y．
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