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。