I borrowed the blue folder from the top shelf, then returned it to that exact spot. Complete with the correct past-tense form based on put, using it to refer to the folder: I ___ after scanning the papers.
Respuesta correcta
put it back
Explicación
Returning the folder to the exact place it occupied calls for put back. Put away would indicate storage in a proper place, but it would not necessarily be the same shelf position described here.