Past Simple в пассивном залоге:
was/were + III форма глагола
This picture was painted in the 16th century.
These houses were built in 1954.
Past Continuous в пассивном залоге:
was/were being + III форма глагола
At six o’clock a story was being told.
They were being watched carefully.
Past Perfect в пассивном залоге:
had been + III форма глагола
All the windows had been cleaned before the storm.
The letter had been written by 5 o’clock yesterday.