A.1倍 B.3-1/2倍 C.1/3倍 D.1/2倍
A.少計(jì)1/3 B.少計(jì)2/3 C.倒計(jì)1/3 D.不計(jì)
A.±0.5Hz B.±0.2Hz C.±0.1Hz D.±1Hz