题目内容：

never once ______(老两口互相争吵）since they were married 40 years ago.答案用的是一般过去式.
可不可以用过去完成时呢?这个since从句的时态使用的具体规则是什么呢?

优质解答

since 后是过去时,之前是现在完成时.若是跟段时间,还可以用一般现在时.如：Great changes have taken place in the city since we met last time.It's ten years \ has been ten years since we met last time.你问...