多少孕周前不能做出前置胎盘的诊断()
A.10周
B.18周
C.28周
D.30周
E.35周
参考答案:C
There is only one seat here. _____ you _____ he can have it. [ ]
A. Neither…nor
B. Either…or
C. Both…and
D. Not only…but also
最低层次的社会保障是( )
A.社会救助
B.失业保险
C.生育保险
D.社会福利