单项选择题
A.<0.4% B.<1.0% C.>1%~1.5%
A.-5%~10% B.-10%~15% C.-15%~25%
A.1.3~1.6kV B.0.38~0.5kV C.2~3kV
A.6.0dB B.3.0dB C.7.5dB
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