题目内容

与来宾交谈时,要聚精会神,切不可 一心二用,所答非所问,更不可忙于其他事务。

A. 对
B. 错

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This modulated carrier is then transmitted to the required destination where it is received and the original information signal is obtained by modulation.

A. 对
B. 错

Sophisticated techniques have been developed for this process by using magnetic carrier waves operating at radio frequencies as well as microwave and millimeter wave frequencies.

A. 对
B. 错

The information source provides an electrical signal to a transmitter comprising an electrical stage which drives an optical source to give modulation of the lightwave carrier.

A. 对
B. 错

The transmission medium consists of an optical fiber cable and the receiver.

A. 对
B. 错

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