单项选择题
A.z/(z-1)B.-z/(z-1)C.1/(z-1)D.-1/(z-1)
A.线性时不变B.线性时变C.非线性时不变D.非线性时变
A.1,0,0,0]B.4,0,0,0]C.1,1,1,1]D.4,j,-j,4]