盐酸吗啡注射液放置过久，颜色变深，这是发生了
A．氧化反应B．加成反应C．聚合反应D．水解反应E．还原反应
参考答案：A
胎膜的组成有（）
A.底蜕膜
B.十状绒毛膜
C.平滑绒毛膜
D.羊膜
E.真蜕膜
Before he finally sent its copies off to be handed out among members of the committee, he went over it again and made sure that no item of importance was ().
A. checked out
B. crossed out
C. dropped out
D. left out
