在数字信号处理中通常定义的数字频率ω是归一化频率，归一化因子为（）。
A.采样周期
B.模拟采样角频率
C.模拟采样频率
D.任意频率
参考答案：C
19. It was in the hotel ________ the famous singer lived _______ she was killed.
A．which; that
B．that; where
C．where; which
D．where; that
经济货币化
