国家规定邮政企业办理（）、国家规定报刊的发行，以及义务兵平常信函、盲人读物和革命烈士遗物的免费寄递等特殊服务业务。
参考答案：机要通信
After the earthquake, the injured were cared ________in the hospitals or taken by air to the hospitals in the neighbouring cities．
A．of
B．for
C．after
D．with
写出信号报警和联锁系统产生误动作的原因。
