钢管在正常气割时，不论割嘴移到何种位置，割嘴均应垂直于钢管的表面。( )
参考答案：错
心电图示P波规律出现，频率65次/分，室性自主节律频率70次/分，应首选下列哪项治疗（）
A.利多卡因
B.胺碘酮
C.心房起搏
D.暂不处理，必要时给予阿托品
E.电复律
E-mail , as well as cellphones, _____an important part in daily communication.
A．have played
B．play
C．are playing
D．is playing
