3.It ___ quite a few years ___ the accused was declared innocent and set free.
问题描述：
3.It ___ quite a few years ___ the accused was declared innocent and set free.
A.was ,since B.is ,that C.will be ,when D.was ,before
为什么不是其他选项?尤其是A?
答
选a话 since 是现在完成时的标志,所以选它就要用完成时,可是题目中用的是was declared是过去时,所以不能选a