解码的任务与编码相反，它是将PCM信号还原为（）信号。
A．模拟
B．数字
C．PAM
D．脉冲
参考答案：C
Niagara Falls is a great tourist _____,drawing millions of visitors every year. [ ]
A. attention
B. attraction
C. appointment
D. arrangement
显象剂是（）液
