"We will have to read nine books."
Translation:Będziemy musiały przeczytać dziewięć książek.
I'm Polish and didn't choose "Będziemy musieć przeczytać dziewięć książek". Apparently it's correct grammatically but nobody really says so. "Będziemy musiały/musieli przeczytać..." sounds much more naturally.
Is there any difference between musiały and musieli? Native speakers can you explain? Thanks a lot.
In past tense, the gender of the subject of the sentence is always visible. So, "będziemy musiały" will be said by a group consisting of women-only. "będziemy musieli" will be said if there is at least one man among 'us'.