管路系统无压力液,操作无动作应如何处理().
A.更换清洗或更换操作阀
B.更换安全阀
C.检修乳化泵
参考答案:A
They are not interested ____________ small quantities.
主动脉瓣狭窄可有
A.S2逆分裂B.心包叩击音C.开瓣音D.Austin-Flint杂音