"Sofia is proud of herself."
Translation:Sofia fieras pri si.
Would the accusative work here instead of the preposition (Sofia fieras sin)?
I forget. Did one of the lessons go over the word "si"? I got this in a practice, by the way, so I don't necessarily know which lesson this is.
I don't know at the moment which lesson introduces si, but I do know that it can be confusing the first few times it is seen (maybe because of its similarity to the Spanish and Italian word for "yes").
It might help to keep in mind the other forms of si: sin, sia, siaj, sian, and siajn (so you won't be so confused the next time you see them).