Just wanted to ask for a few German phrases.

The phrases are "You are annoying me" and something along the lines of "(I swear) I'm going to kill you". Understandably, tourist German phrase books aren't a lot of help.

Also, what would a child call a rabbit? Is it different to what an adult would call a rabbit? Such as bunny/rabbit in English? And what might a child call their stuffed rabbit (a name like Mr. Rabbit)?

Lastly, how would a tutor say "Study harder" in German?

Thanks for any help on this I'm wary of online translations after seeing how they mangle Japanese and Greek phrases :P