单项选择题
A.16%-18%B.13%-15%C.11%-12%D.9%-11%
A.26.7-40.0kPaB.30.0-50.0kPaC.16.7-40.0kPaD.36.7-40.0kPa
A.4-8分钟B.3-5分钟C.10-28分钟D.8-12分钟