单项选择题
A.10~15sB.15~30sC.25~30sD.30~50s
A.800~1000PaB.1000~2000PaC.2000-3000PaD.3000~4000Pa
A.1200~1300PaB.1000~2000PaC.2000~3000PaD.3000~4000Pa