单项选择题

A.3.92kPa(>40cmH20)
B.1.96~3.92kPa(20~40cmH20)
C.1.47~1.96kPa(15~20cmH20)
D.0.98~1.47kPa(10~15cmH20)
E.0.49~0.98kPa(5~10cmH20)