Measure the time necessary for the pressure to decrease.( )
A.Time the pressure decay. B.Count the time necessary for the pressure to decrease. C.Record the time for the pressure to go upwards.正确答案B
Measure the time necessary for the pressure to decrease.( )
A.Time the pressure decay. B.Count the time necessary for the pressure to decrease. C.Record the time for the pressure to go upwards.正确答案B