英语现在完成时和过去完成时的区别和用法

Answer 1

从时间上而言，现在完成时是现在时态，而过去完成时是过去时态。
用法：
现在完成时：过去的动作影响现在，就是过去动作与现在有关系。如
He has seen the film and he saw it last night.
过去动作（持续性）或状态持续至今，也可能继续持续下去。如
He has stayed here for two years.
过去完成时：过去之前的动作或状态，也就是过去的过去。得先有过去，才会有过去的过去！
He had seen the film before he came to our city.