单项选择题
A.1 B.2 C.3 D.4 E.5
A.250–1000Hz B.1000–20000Hz C.5000–8000Hz D.2000–3000Hz E.4000–6000Hz
A.50% B.40% C.30% D.20% E.70%
A.60db B.55db C.50db D.45db E.40db
微信扫一扫,加关注免费搜题
