单项选择题
A.1.1MPa,0.9MPaB.1.0MPa,0.8MPaC.1.0MPa,0.7MPaD.0.9MPa,0.6MPa
A.5B.10C.20D.30
A.1.8~1.5B.1.6~1.4C.1.5~2.0D.1.6~2.0