A、<p><span style="font-family: 宋体; font-size: 17.1429px; ">干线式</span></p>
B、<p><span style="font-family: 宋体; font-size: 17.1429px; ">树干式</span></p>
C、<p><span style="font-size: 14px; font-family: 宋体;">电链式</span></p>
D、<p><span style="font-family: 宋体; font-size: 17.1429px; ">放射式</span></p>