A.≤0.04dB、≤0.1dB B.≤0.08dB、≤0.14dB C.≤0.64dB、≤0.12dB D.≤0.12dB、≤0.38dB
A.300-500 B.500-1000 C.1000-2000 D.2000以上
A.0.1-0.2m B.0.2-0.4m C.0.3-0.5m D.0.4-0.6m