主干电缆
参考答案：
一般是指总配线架与电缆交界箱之间的电缆。
My mother is ill. The doctor said that she had to _____ at once. [ ]
A. operate
B. be operated
C. operate on
D. be operated on
读下面的风向示意图，当风速稳定后，下列叙述正确的是
A．等压线数值①＜②＜③
B．a是地转偏向力
C．此风形成于南半球
D．该风形成于高空
