Past Tense—Passive Voice
(Substitute be seen for be in the past potential of to be.)
Present Perfect Tense—Active Voice
Simple
(Substitute have seen for be in the present potential of to be.)
Progressive
(Substitute have been seeing for be in the present potential of to be.)
Present Perfect Tense—Passive Voice
(Substitute have been seen for be in the present potential of to be.)
Past Perfect Tense—Active Voice