In the scond sentence "roto" (broken) is a past participle, it is not an adjective. Thus it cannot change as the adjective "roto" would. Let me give you another sample. My sister will marry Chris. My sister has married Chris. My sister is married. Mi hermana se casará con Chris. Mi hermana se ha casado con Chris. Mi hermana es casada. Even when the subject of the second sentence is feminine the past participle remains with "o" because it is a fixed form. In the third sentence "married" is an adjective, thus.in Spanish the "o" has to change to "a" to agree with the feminine subject.

Hi! In Spanish it should be: "se ha roto la ventana" o "la ventana se ha roto" verbo auxiliar "haber" + participio. Por ejemplo, "Tenías que haber comido menos, ahora te dolerá la barriga" "¿has vivido en España alguna vez?" Quizá esta web te ayude: http://www.wordreference.com/conj/EsVerbs.aspx?v=romper Saludos, Juan.