单项选择题
A.0.08～0.12s B.0.06～0.08s C.0.08～0.20s D.0.06～0，10s E.0.08～0.11s
A.肢体导联<0.25mV，胸前导联<0.15mV B.肢体导联<0.20mV，胸前导联<0.25mV C.肢体导联<0.25mV，胸前导联<0.25mV D.肢体导联<0.25mV，胸前导联<0.20mV E.肢体导联>0.25mV，胸前导联<0.20mV
A.从心尖部向心底部方向观测 B.从右心房向心底部方向观测 C.从前向后观测 D.从水平面观测 E.从心尖部向右心室观测