is 'acabado' acceptable instead of 'terminado'?
I certainly believe so.
By itself, "acabar" means "to finish" or "to end".
I submitted 'He terminado este capitulo,' and was marked incorrect. It it really necessary to add 'yo?'
No necessary, Duo just doesn’t have your answer in their database.
I think 'acabar' (usually used with 'de') means 'just finished' as in 'he acabado de escribir un mensaje a duo'
Why not use: esto capitulo
Why is yo there?
He cumplido este capitulo. What is wrong with this.