不让压力变为20psi以下。( )
A.Do not let the pressure go below 20 psi. B.Do not decrease the pressure to 20 psi C.Do not let the pressure become less than 20 psi.正确答案C
不让压力变为20psi以下。( )
A.Do not let the pressure go below 20 psi. B.Do not decrease the pressure to 20 psi C.Do not let the pressure become less than 20 psi.正确答案C