产后出血原因中哪项首先考虑用子宫切除的方法止血（）
A.子宫收缩乏力
B.胎盘植入
C.胎盘嵌顿
D.凝血功能障碍
E.胎盘粘连
参考答案：B
_______ your son is well again, you no longer have anything to worry about.[ ]
A. If
B. when
C. Now that
D. As soon as
急性胆囊炎的病因和发病机制。
