子宫收缩乏力易发生（）
A.软产道裂伤
B.胎盘滞留
C.胎盘粘连
D.胎盘嵌顿
E.凝血功能障碍
参考答案：B
So sudden _______that the enemy had no time to escape. [ ]
A. did the attack
B.the attack did
C. was the attack
D.the attack was
震源尺度是从地震记录求得的（）表征的参数。
