You coould say "¿Ha terminado el ejercicio?"
it was finished when they stop working on it.
"I am done" translates to "he terminado", as in "I have finished". In Spanish, we say "Ya termine" (I finished already)
Trabajando
Working ~ trabajando
Yes it is, unless the person who finished the project is named "Finally". Your sentence needs a subject like "I finally finished..." In some languages, like Spanish, the subject would be understood because the verb makes it clear. English requires the noun to accompany the verb.
stocks and finished goods
yes
stocks of finished goods
stocks of finished goods
He was an explorer, Spanish by birth and working for Spain.
trabajo
working