QRS波群低电压，可见于（）
A.肺气肿
B.心包积液
C.心肌梗死
D.肥胖
E.心肌淀粉样变
参考答案：A, B, C, D, E
We have worked for such a long time. Shall we stop _______ a rest? [ ]
A. having
B. to have
C. have
D. had
( )是指能造成生命和财产损失的偶发事件，它是造成损失的直接原因或外在原因，是损失的媒介质。
A．风险因素
B．风险事故
C．风险损失
D．风险投资
