如果用连接卸扣代替连接链环，则连接卸扣的圆弧部分应（）。
A. 全部朝向锚
B. 全部背向锚
C. 部分朝向锚
D. 部分背向锚
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调频广播的频率范围为（）~（）MHz；通常电波的极化方式为水平极化；发射功率>50W的电台，载频允许偏差为（）Hz，发射功率≤50W的电台，载频允许偏差为（）Hz。
The main function of the core of a wire rope is to（）.
A. give flexibility
B. support the strands laid around it
C. allow some circulation around the strands
D. allow lubrication inside the rope
What two descriptions best define DWDM？ （）
A. a WDM system that is compatible with EDFA technology
B. an optical technology for transmitting up to 16 channels over multiple fiber strands
C. an optical technology for transmitting up to 32 channels over multiple fiber strands
D. a technology for transmitting multiple optical signals using less sophisticated transceiver designthen CWDM
E. a technology for transmitting more closely packed optical signals using more sophisticatedtransceiver designs than CWDM
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