A:must have worked
B:can have worked
C:will have worked
D:has worked
某报驻华记者在回忆录中提到“誓死力争,还我青岛”“外争主权,内出国贼”、“释放被捕学生”等内容,那么,他回忆的历史事件是( )
抛物线y=2(x+3)2+4的对称轴的方程是( )