合同是份确定当事人一定（）的协议。
参考答案：权利和义务
Unfortunately, when I arrived, Mary , so we only had time for a few words.
A．was just leaving
B．just left
C．has just left
D．had just left
子宫收缩乏力可导致
A．胎盘剥离后滞留B．胎盘嵌顿C．胎盘粘连D．胎盘剥离不全E．凝血功能障碍
