WHO + DO
Cuando es sujeto del verbo, who no utiliza auxiliar en preguntas: Who went with you? Who spoke first? Who kicked you in the butt? Who comes here at five o’clock every day? Si no es sujeto sí necesita el auxiliar do : Who did you play with? Who does she sleep with? (Aquí you y she son los sujetos del verbo) Consultar mi GRAMÁTICA INGLESA PARA TORPES , en papel o e-book, de Anaya Multimedia, 2013.