Have you seen the film?（强调是否了解电影的内容）

Did you see the film? （暗指何时何地看过这部电影）

1.一般过去时表示的动作或状态都已成为过去，与现在没有联系；而现在完成时表示过去发生的动作对现在产生的结果或影响，与现在有联系．

Her bike was broken.(或许修好了，或许没修好)

Her bike has been broken.(至今未修好。)

He lived here all his life.  (已死)

He has lived here all his life. (他还活着）

2. 句子中如有过去时的时间副词（如 yesterday, last week, in 1960）时，不能使用现在完成时，要用过去时。例如：

(误) He has written a letter to his parents last night. 

(正) He wrote a letter to his parents last night.