单项选择题
A.1种B.2种C.3种D.4种E.5种
A.仪器用品准备B.环境准备C.了解病情D.和患者取的互相了解和信任E.无相关培训认证均可
A.2~80HzB.30~100HzC.30~1000HzD.100~1000HzE.1000~2000Hz