过去分词表示被动,与have/had一起构成完成时态.
过去式在句中表示动作发生在过去.
只能是：I have been seen.
I have seen it.
I saw it.
I had seen it.
I had been seen.那请问 I have been seen it.与 I saw it.有什么区别？不能用I have been seen it. 因为这是被动式，宾语提前变成主语。我已经被看见了。I saw it. 我过去看见它了。