下列属于社会保险的有（）。
A.养老保险
B.失业保险
C.医疗保险
D.工伤保险
参考答案：A, B, C, D
6只鸽子飞回3个鸽舍总有一个鸽舍至少要住上______只鸽子．
7只鸽子飞回3个鸽舍总有一个鸽舍至少要住上______只鸽子．
8只鸽子飞回3个鸽舍总有一个鸽舍至少要住上______只鸽子．
The book, which is a useful guide for today's young people, deals with many questions and problems that face them at school and at home as well as in society.
A．are faced
B．confront
C．in opposition
D．meet.
