单项选择题
A.0.5倍~2.0倍B.1.0倍~2.0倍C.1.5倍~2.0倍D.1.5倍~3.0倍
A.0.1Hz~100HzB.0.1Hz~200HzC.1Hz~100HzD.1Hz~200Hz
A.一B.二C.三D.四