单项选择题
A.1% B.4% C.2% D.5%
A.集中检修 B.重点整治 C.日常维护 D.重点维修
A.0dBr;-6dBr B.-1dBr;-5dBr C.0dBr;-7dBr D.-1dBr;-6dBr
A.800Hz B.1020Hz C.1000Hz D.2408Hz
微信扫一扫,加关注免费搜题