问题：
Recently I was an observer at _____ parent education seminar about the depression, suicide, and anxiety disorders affecting _____ children.
A．the ; the
B．the ; a
C．a ;
D．a ; the
Recently I was an observer at _____ parent education seminar about the depression, suicide, and anxiety disorders affecting _____ children.
| A．the ; the | B．the ; a | C．a ; | D．a ; the |
参考答案：