心脏的正常起搏点是（）
A.窦房结
B.房室束
C.普肯耶纤维
D.左、右束支
E.房室结
参考答案：A
The experiment shows that proper amounts of exercise, if __ regularly, can improve our health.
A．being carried out
B．carrying out
C．carried out
D．to carry out
简述临产后 * * 检查的适应证。
