题干
It _____ quite a few years _____ the accused was declared innocent and set free.
A：was; since
B：is; that
C：will be; whe
D：was; before
答案(点此获取答案解析）
D
A：was; since
B：is; that
C：will be; whe
D：was; before
的图象关于直线
对称的充要条件是