临产后出现胎心异常，易造成胎盘早剥（）
A.脐带先露
B.脐带脱垂
C.脐带缠绕
D.脐带长度异常
E.脐带扭转
参考答案：D
30. the grand graduation ceremony ,which thousands of the graduates _____ last night, was more successful than we had expected.
A．appointed
B．absorbed
C．attended
D．attracted
