"Su departamento de publicidad ha sido lento."
Traducción:Their advertising department has been lazy.
Cuándo se desconoce si la persona es un él o un ella, generalmente utiliza their.
Why can't I write "advertisement" and "slow" instead of "advertising" and "lazy". I need an answer and an explanation in order to continue learning well this language
Don't worry, if you were saying that in English you would be completely understood. To me as an English speaker they should both be accepted. I was doing timed practice and entered "their advertising department has been slow" and it would not accept that either. My other problem was that my time ran out before I could report that my answer should be accepted.
cuando no se sabe si el sujeto es masculino o femenino muchas veces se usa they/them/their para reemplazar his/her pero sigue siendo singular. espero haber respondido tu pregunta!