Questions & Answers about Onu sen değil, ben eledim.
Why do we need the pronouns sen and ben here if eledim already means "I eliminated"?
This sentence perfectly shows how focus (vurgu) works. The word immediately before the verb gets the strongest emphasis. By explicitly writing ben and placing it right before eledim, the speaker stresses that they are the one who did it. The pronouns are required here to create the contrast: not you, but me.
I thought action verbs were negated with -me or -ma. Why use değil here?
You use the -me suffix to negate the action itself (like elemedim for "I did not eliminate"). But here, the action actually happened. The speaker is negating the subject, not the verb. To say "not you" in the middle of an action sentence, you use the pronoun plus değil (sen değil).
Why does onu come at the very beginning of the sentence instead of closer to the verb?
In Turkish, the beginning of the sentence is for the "topic" or the background information we already know about. Onu (him) is placed first to establish who we are talking about. This pushes the new, contrasting information (ben) to the pre-verbal focus position, which is the most important spot in the sentence.
Why is it onu instead of just o?