Rules to Remember
When rewriting active sentences in passive sentence, note the following:
¢the object of the active sentence becomes the subject of the passive sentence
¢the finite form of the verb is changed (to be + past participle)
¢the subject of the active sentence becomes by Agent in the passive sentence (or is dropped)
¢Only active sentence containing object which can be changed into passive form
¢The two forms should have the same tenses

Type of Passive
¢Awkward Passive:  My bicycle was repainted by John.
¢Deliberate Passive:  My bicycle was repainted.  (The performer is not mentioned and the emphasis is on the bicycle.)

A sentence is written in active sentence when the subject of the sentence performs the action in the sentence.
[Subject] + [To be] + [Ving] + [Object]
                A sentence is written in passive sentence when the subject of the sentence has an action done to it by someone or something else.
[Object] + [To be] + [Verb3] + [by Subject] 


FORMULA OF ACTIVE AND PASSIVE SENTENCES IN PRESENT TENSE
Simple Present Tense
Active      : S + V1 (s/es) + O , comp.
Passive    : O + To Be (am, is, are) + V3 + by S + comp.
Present Continuous Tenses
Active     : S + To Be + V.ing+ O+ comp.
Passive   : O + To Be (am, is, are) + Being + V3 + by S + comp.
Present Perfect Tense
Active    : S + has/have + V3 + O, comp.
Passive  : O + has/have + been + V3 + by S + comp.
Present  Perfect Continuous  Tense
Active   : S + has/have + been + V.ing + O+ comp.
Passive : O + has/have+ been + being + V3 + by S + comp 
 FORMULA OF ACTIVE AND PASSIVE SENTENCES IN PAST TENSE
Simple Past Tense
Active   : S + V2 + O, comp.
Passive : O + To Be (was, were) + V3 + by S + comp.
Past Continous Tense
Active    : S + To Be(was, were) + Ving + O, comp.
Passive  : O+ To Be (was, were) + being + V3 + by S + comp.
Past Perfect Tense
Active    : S + HAD + V3 + O, comp.
Passive  :O + Had + been + V3 + by S + comp.
Past Perfect Continous Tense
Active     : S + had been+ving + O, comp.
Passive   : O+ had+been +being + V3 + by S + comp.
FORMULA OF ACTIVE AND PASSIVE SENTENCE IN FUTURE TENSE
Simple Future Tense
Active   :  S + WILL + V1 + O, comp.
Passive :  O+ WILL BE + V3 + by S + comp.
Future Continous Tense
Active   : S + WILL BE+ V1 + ING + O, comp.
Passive : O + WILL BE + BEING + V3 + by S + comp.
Future Perfect Tense
Active    : S + WILL HAVE+V3 + O, comp.
Passive  : O + WILL HAVE + BEEN + V3 + by S + comp.
Future Perfect Continous
Active     : S +WILL HAVE BEEN+VING + O, comp.
Passive   : O + WILL HAVE + BEEN + BEING + V3 + by S + comp
FORMULA OF ACTIVE AND PASSIVE SENTENCES IN PAST FUTURE TENSE
Past Future Tense
Active    : S +WOULD + VERB 1 + O+ comp.
Passive  : O + WOULD BE+ V3 + by S + comp.
Past Future Continuous Tense
Active     : S +WOULD BE+V.ING + O, comp.
Passive   : O + WOULD BE + BEING + V3 + by S + comp.
Past Future Perfect Tense
Active     : S +WOULD HAVE + V3 + O, comp.
Passive   : O+ WOULD HAVE + BEEN + V3 + by S + comp.
Past Future Perfect Continuous Tense
Active    : S +WOULD HAVE +BEEN+V.ING + O+ comp.
Passive  : O + WILL HAVE + BEEN + BEING + V3 + by S + comp.

MODALS
Active   : S +MODALS + V1+ O, comp.
Passive : O + MODALS BE+ V3 + by S + comp.