假设群体又称（）。
A.假象群体
B.统计群体
C.实际群体
D.虚拟群体
参考答案：B
As far as I know, this maths problem is _______________ that one.
A．twice so difficult as
B．twice as difficult as
C．as twice difficult as
D．so twice difficult as
自主就业的退役士兵回乡后，没有土地怎么办？
