"¿Quién escribió la introducción?"
Translation:Who wrote the introduction?
Eso es lo que le dices a tus amigos cuando salen mal en un trabajo/informe de la escuela y la parte incorrecta era la introducción :P
A bit awkward, I think, although grammatically 'correct.' In my part of the English speaking world, it would be 'wrote.' The 'did write' version would be used for asking a question = "Did you write the introduction?"
When the interrogative particle is the subject or part of the subject (who), you do not have to use auxiliary (do, does, did):
Who wrote Romeo and Juliet? How many students played basketball?
but if the particle is not the subject, you have to use it:
Who did you see? How many books did they publish?