不属于50Hz干扰源的是（）
A.电扇
B.电灯
C.透热疗法
D.灯光调光器开关
E.心脏起搏器
参考答案：E
伴有消化性溃疡的高血压患者不宜用
A．利血平B．哌唑嗪C．心得安+双氢克尿噻D．罗布麻E．可乐宁
23. The class is unusual_______ the students are all over fifty and none of them attended the middle school when they were young.
A．in how
B．in what
C．in which
D．in that
