[kentosi]

If you're having trouble understanding passive voice, then think of it this way:

The passive voice means that you don't actually have to put in the person/thing doing the action, and the sentence will be gramatically correct and complete.

See these examples:

Active: The burgler robbed the bank. Passive: The bank was robbed by the burgler. Passive - doing person: The bank was robbed. Note: You can't do this with the active voice, unless you say "someone robbed the bank".

Active: I ate the cake. Passive: The cake was eaten by me. Passive - doing person: The cake was eaten.

I hope this makes sense?