第21题: [单项选择]A full ______ of all the reasons for and against closing the railway has begun. A. explosion B. exploration C. exploitation D. explanation 参考答案:D 答案解析:explanation解释,说明;explosion爆炸;exploration探险;exploitation剥削,利用。句子意思是人们畅所欲言,开始解释支持或反对关闭铁路的理由。
第22题: [单项选择] A user plugged a cable between two network jacks that attach to the same switch and caused a broadcast storm. Which of the following would have prevented the broadcast storm?() A. Spanning tree B. VLAN tagging C. 802.1x D. Port mirroring 参考答案:A