现在完成时与过去完成时有什么区别,举例子 谢谢

现在完成时强调对现在的影响.时间是从过去起延续至现在,所以常和since,so far; up to now; up to the present 连用
He has so far made no suggestions in any shape or form.
她至今没有提出任何建议.
A lot of [Lots of] work has been done by her since yesterday.
昨天以来她己做了大量的工作.
过去完成时是相对过去某一特定时点来说某个动作发生了,或是某种状态已经存在,指的是过去的过去
如：
When I got to(过去）the station,the train【 had left】(更早的过去）