How to say:
Comment was already voted by you
In this sentence I mean that someone made some choice about a comment and I want to tell him about it. Please help me to make my sentence correct and explain to me the correct grammar being used.
I think what you're looking for is something like
The comment was voted on by you.
or
You already voted on the comment.
or the simpler
You voted on the comment.
If you were to specify the vote (either 'yes' or 'no', for example) then no preposition would be necessary:
He voted yes. -or- He voted yes on the comment.
This shows that the subject of the vote (the comment) is voted on while the result of the vote does not need the preposition.