A.0.9~1.0倍 B.1.0~1.2倍 C.1.2~1.4倍 D.1.4~2.0倍
A.額定功率 B.額定電壓 C.額定電阻 D.額定電流
A.平衡的嗡嗡聲 B.有節(jié)奏的嗡嗡聲 C.輕微的嗡嗡聲 D.沒(méi)有聲音