"He is my literature professor."
Translation:Él es mi profesor de literatura.
This does not require that él be included. The subject is implied by verb form and is not required.
Él or La may not be required, but without the setting and circumstances of the sentence, "Él" provides needed clarification. At least we now know that they're talking about a particular man. Before, the clarification was missing and we had not much of a clue as to who they were talking about other than someone who is a history professor. While it may be consistent with Spanish grammar rules that "Él" is not needed, for clarity, it is needed. DuoLingo in including the "Él" has required better communication than we would have without the"Él." That is not a bad grammar point either, even if technically, it is not required.
Tried using maestro instead of profesor. Didnt work. What do you guys think, close enough or not quite?
Not quite. While both a teacher and a professor teach, they are different words, and usually in the scheme of education, at different levels of the education process. Good luck with your Spanish.
Why isn't catedrático accepted? 'profesor' means teacher whereas 'catedrático' means professor ....
7/8/2014 still nothing changed, it requires "El" to be correct... c'mon it's been months since reporting it///
9/07/14 "Es mi profesor de literatura" is still incorrect :/