passive voice

what is the meaning of passive voice?
passive voice is a sentence in which the subject is affected an action of the verb. The general form of passive is "to be + V3." Passive voice focus in an action. You have to notice that passive voice is formed by transitive verbs (need object) and the second rule is "don;t ever change the tenses."
For example: ACTIVE   = Cuplis buy a book
                     PASSIVE  = a book is bought by Cuplis

passive in simple present (am/is/are + V3)
A: Panjul sell the car
P: the car is sold by Panjul


Passive in Simple Past (was/were + V3)
A: Mansyuur ate meal
P: meal was eaten by Mansyuur


Passive in Present Continuous (have/has + been + V3)
A: She has broke the computer
P: the computer has been broken by her


Passive in future (will/th be going to + be + V3)
A: I am going to repair this computer            A: My father will buy a new car
P: this computer is going to be repaired         P: a new car will be bough by My father


Passive with modals (may, will, should, can, etc) (modal + be + V3)
A: I can write a letter
P: the letter can be written by me