这个句子的完成时可以改成过去式么?

这个句子的完成时可以改成过去式么?
1、He refused to go until he had seen（saw） all the papers.
2、After the will had been（was） read,there were angry exclaimations.
3、Before I had known（knew可以么?） him for a week,he tried to borrow money from me.
4、My friend explained that the house had been (was可以么)originally built as a monastery but had been（was可以么） converted into a manor when monasteries were dissloved under Henry.