在单工通信方式中,信号只能向一个方向传输。例如:无线广播电台的广播。()
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若检修设备属于同一电压等级、位于同一楼层、同时停送电。且工作人员不会触及带电导体时,则在几个电气连接部分()。
A. 可以共用一张工作票
B. 必须使用两张工作票
C. 有几个电气连接部分,必须使用几张工作票
通信子网可分为点—点通信线路通信子网与广播信道通信子网两类。()
The passage contains information that would answer which of the following questions? I . What techniques have industrialists used to manipulate a free market? II . In what ways are "New World" and " Old World " economic policies similar? III. Has economic policy in the United States tended to reward independent action?
A. I only
B. II only
C. III only
D. I and II only
E. II and III only
是()。
A. 液上喷射中倍数泡沫灭火系统
B. 液下喷射低倍数泡沫灭火系统
C. 液上喷射低倍数泡沫灭火系统
D. 液下喷射中倍数泡沫灭火系统