以下选项中，属于广域网的是________。
A．宿舍网
B．国家网
C．校园网
D．楼宇网
参考答案：B
Some parts in south China have experienced _____ this year as they did last year.
A．twice as much rain
B．rain twice as much
C．as twice much rain
D．twice rain as much
简述人员密集场所发生火灾时的扑救对策？
