We use the simple past tense for actions that began and finished in the past. We do not have to say exactly when. The important thing is that it happened and is not happening now.
'I saw it'
The past participle is used with the following tenses:
I have seen it.
I had seen it.
I will have seen it.
I would have seen it.
It was seen.
Read through the following sentences and choose the correct verb tense to complete each sentence.