A.升高B.不变C.降低D.形成真空
A.0.05-0.10mmB.0.10-0.20mmC.0.20-0.30mmD.0.30-0.40mm
A.吸气阀、排气阀打开B.吸气阀、排气阀关闭C.吸气阀打开、排气阀关闭D.吸气阀关闭、排气阀打开