I have always wanted to improve my Latin writing, so I've decided to work through North and Hillard's Latin Prose Composition. I have the accompanying key, so I'm able to check my answers, but I'm having a hard time understanding why my answer is incorrect for Exercise 25 Sentence 3.
25.3: The soldiers, throwing away their arms, fled from the battle. My translation of this was Milites arma abicientes e proelio effugerunt. The key offers Milites, armis abiectis, e proelio effugerunt.
I don't understand why a present active participle can't be used. The participial phrase agrees with the subject of the sentence, so as far as I understand it, you don't need to use an ablative absolute - but the answer key uses one.
I understand that the answer key will only offer one possible translation (out of many possibilities), and translations won't always match the key, even if they're correct. Is that what is going on here?