等容收缩期的定义是()。
A.心房去极化期
B.二尖瓣关闭到主动脉瓣开放间期
C.二尖瓣叶开放的第一个峰
D.心室快速充盈早期
E.心室舒张晚期
参考答案:B
In the context of corporate governance, explain how the decision-making power is divided between the shareholders in a general meeting and the board of directors. (10 marks)
预防近视和龋齿是学龄儿童保健的重点之一,一般每年做眼.口腔检查一次,预防屈光不正.龋齿的发生。