求高人帮我分析分析现在完成时和过去完成时还有过去时的区别?完全懵了!.两个句子都出自高一英语必修一的一篇文章：Anne's best friend1、She and her family hid away for nearly 25 months before they were discovered.这个句子中的hid away是一个普通的过去时,但是后面却接了一个for+时间段,那么这句子不是应该用现在完成时吗?即：She and her family have hidden away for nearly 25 months before they were discovered.这样不才是正确的吗?2、I can well remember that there was a time when a deep blue sky,the song of the birds,moonlight and flowers could never have kept me spellbound.这个句

求高人帮我分析分析现在完成时和过去完成时还有过去时的区别?完全懵了!.
两个句子都出自高一英语必修一的一篇文章：Anne's best friend
1、She and her family hid away for nearly 25 months before they were discovered.这个句子中的hid away是一个普通的过去时,但是后面却接了一个for+时间段,那么这句子不是应该用现在完成时吗?即：She and her family have hidden away for nearly 25 months before they were discovered.这样不才是正确的吗?
2、I can well remember that there was a time when a deep blue sky,the song of the birds,moonlight and flowers could never have kept me spellbound.这个句子的have kept是一个现在完成时,请问在句中哪里体现了要用上现在完成时,我个人觉得反倒是直接用上一个keep才最正确,即：.could never keep me spellbound.这样才是正确的.
还有就是想问一下,现在完成时和过去完成时在一定条件下是不是可以对换的?一般而言,过去完成时就是多了一个"时间与时间的比较",而现在完成时是没有时间与时间的比较的.例如：The bus has gone./The bus had gone at that time.其实不管是现在完成时还是过去完成时都好,都有包含“过去”的意思是吗?两个句子中,汽车其实都是“已经走了”,注意是“已经”,所以可以说明两种时态都是有包含“过去”之意?但是如果要更加具体地表明在哪一个时间段走了的,就要用到过去完成时.