单项选择题
A.39.2kPa,4mH2O B.58.8kPa,6mH2O C.34.3kPa,3.5mH2O D.19.6kPa,2mH2O
A.3 B.3.25 C.4 D.4.75
A.10.5 B.8.5 C.6.5 D.7.5