PASSIVE TENSES AND ACTIVE EQUIVALENTS

Notice that the tense of the verb to be in the passive voice is the same as the tense of the main verb in the active voice.
to keep
TENSE / VERB FORM ACTIVE VOICE PASSIVE VOICE
Simple present
keeps
is kept
Present continuous
is keeping
is being kept
Simple past
kept
was kept
Past continuous
was keeping
was being kept
Present perfect
have kept
have been kept
Past perfect
had kept
had been kept
Future
will keep
will be kept
Conditional Present
would keep
would be kept
Conditional Past
would have kept
would have been kept
Present Infinitive
to keep
to be kept
Perfect Infinitive
to have kept
to have been kept
Present Participle/Gerund
keeping
being kept
Perfect Participle
having kept
having been kept
Example sentences:
Active: I keep the butter in the fridge.
Passive: The butter is kept in the fridge.
Active: They stole the painting.
Passive: The painting was stolen.
Active: They are repairing the road.
Passive: The road is being repaired.
Active: Shakespeare wrote Hamlet.
Passive: Hamlet was written by Shakespeare.
Active: A dog bit him.
Passive: He was bitten by a dog.