单项选择题
A.2对 B.3对 C.4对 D.8对
A.6级 B.8级 C.10级 D.12级
A.27dB B.29.2dB C.30dB D.36dB
A.-36VDC—-57VDC B.42VDV—58VDC C.180VAC—240VAC D.-45VDC—-60VDC
微信扫一扫,加关注免费搜题
