Somebody invented the wheel 4.000 years BC.
Who invented the wheel is not known in this case, but the object, the wheel, is very important and we can make of an object the subject of a sentence in the passive voice.
So we can say that : The wheel was invented 4000 years BC.
Where the wheel is now the subject of the sentence
- Active: Somebody invented the wheel 4000 years BC.
- Passive: The wheel was invented 4000 years BC.
Sometimes the subject of the active sentence is also important , in this case we can keep it as the agent in the passive voice.
Admiral Nelson, the one on top of his Column at Trafalgar Square in London and my son, the one with the hood
Active: Lord Nelson won the battle of Trafalgar.
Passive: The battle of Trafalgar was won by Lord Nelson.
Let me try with another example:
William Shakespeare wrote Hamlet
The author is very important and the play too,
in this case we must talk about both in the Passive voice.
Active: William Shakespeare wrote Hamlet
Passive: Hamlet was written by William Shakespeare
How do we build the passive voice?
- The object of the active sentence becomes the subject of the passive one.
- The verb to be must be in the same tense as the main verb of the active voice.
- The main verb of the active sentence comes in the Past Participle.