S12交换机对数字树一般分成两种:一种是(),另一种是()。
参考答案:依赖于源的树;公共树
腰椎间盘突出最常压迫的神经根是()
A.L2和L3神经根
B.L3和L4神经根
C.L4和L5神经根
D.L5和S1神经根
E.S1和S2神经根
The hurricane damaged many houses and business buildings; _____, it caused 20 deaths. [ ]
A. or else
B. therefore
C. after all
D. besides