"Am început omorând doi iepuri."
Translation:I started killing two rabbits.
Why should it be ? If it was a protracted process (or one that changed - "I started killing two rabbits but then changed my mind/decided to kill fifty/etc.) then this is perfectly good English ...
Well something definitely has to be changed, but considering the fact that it's an exercise where the Romanian sentence is given, and you have to provide the English translation, I suppose it makes most sense to rectify the English sentence.
And in case you missed it:
- Am început omorând doi iepuri. = I started by killing two rabbits.
- Am început să omor doi iepuri. = I started killing two rabbits.