.It is said that the early European playing-cards ______for entertainment and education.

A．were being designed

B．have designed

C．have been designed

D．were designed

患者男性，37岁，偶发心悸。心电图如图5-13所示，应诊断为（）。

A.二度Ⅱ型窦房阻滞

B.窦性停搏

C.窦性心律不齐

D.交界性期前收缩

E.房性期前收缩未下传