醉酒的人在醉酒状态中，对本人有危险或者对他人的安全有威胁的，应当将其拘留到酒醒。( )
参考答案：错
铁路局电务监测中心应用服务器采用（）技术，作为整个铁路局微机监测系统的控制中心。
A.单机结构
B.双机冗余
C.三取二
D.二取二
__ many times, but she still didn't know how to do it.
A．She was taught
B．Having taught
C．Having been taught
D．She has taught
