补充区域是中心地的周围从中心地接受（）供给的区域。
参考答案：中心地
It was Tom as well as two of his classmates that _______ invited to the party.
A．was
B．were
C．has
D．have
常引起脊柱不稳的脊椎骨折是（）
A.椎体前柱骨折
B.椎体中柱骨折
C.椎体后柱骨折
D.椎体压缩性骨折
E.以上都是
