食管心房调搏时,造成心房起搏失败的原因是()。
A.起搏频率不合适
B.起搏电压过低
C.食管电极导管折断
D.食管电极导管的位置不适当
E.以上都是
参考答案:E
Choose the appropriate letters A-C.
People usually have A. a mixture of fingertip patterns which are identical on each hand. B. a mixture of patterns with similarities between hands. C. a different pattern on each hand.
仔猪黄痢最常发生的年龄是()。
A、3日龄
B、7日龄以上
C、各种年龄
D、1月龄