风险是保险产生和存在的（）
A.前提
B.环境
C.可能
D.证明
参考答案：A
It is not rare in_____ that people in ______ fifties are going to university for further education．
A．90s ; the
B．the 90s; /
C．90s; their
D．the 90s ; their
物证
