单项选择题
A.0.2kPaB.2.25mmHgC.0.5kPaD.6mmHg
A.0.2kPaB.3.75mmHgC.0.5kPaD.2.25mmHg
A.(-0.2~0.2)B.(-0.5~0.5)C.(0~0.5)D.(-0.2~0.5)