单项选择题
A.±0.2% B.±0.5% C.±1.5%
A.0.10% B.0.20% C.0.30%
A.±2ms B.±3ms C.±4hs
A.3S B.4S C.5S
A.1S B.2S C.3S
A.2S B.3S C.4S
A.4min B.5min C.6min